Mae gwenithfaen yn fath o graig igneaidd sy'n cael ei gloddio am ei gryfder, ei ddwysedd, ei wydnwch a'i wrthwynebiad eithafol i gyrydiad. Ond mae gwenithfaen hefyd yn amlbwrpas iawn - nid dim ond ar gyfer sgwariau a phetryalau y mae! Mewn gwirionedd, rydym yn gweithio'n hyderus gyda chydrannau gwenithfaen wedi'u peiriannu mewn siapiau, onglau a chromliniau o bob amrywiad yn rheolaidd - gyda chanlyniadau rhagorol.
Through our state of the art processing, cut surfaces can be exceptionally flat. These qualities make granite the ideal material to create custom-size and custom-design machine bases and metrology components. Granite is:
■ peiriannadwy
■ union wastad ar ôl ei dorri a'i orffen
■ gwrthsefyll rhwd
■ gwydn
■ parhaol
Mae cydrannau gwenithfaen hefyd yn hawdd i'w glanhau. Wrth greu dyluniadau wedi'u teilwra, gwnewch yn siŵr eich bod yn dewis gwenithfaen oherwydd ei fanteision uwch.

SAFONAU / CEISIADAU GWISGO UCHEL
Mae gan y gwenithfaen a ddefnyddir gan ZHHIMG ar gyfer ein cynhyrchion platiau arwyneb safonol gynnwys cwarts uchel, sy'n darparu mwy o wrthwynebiad i wisgo a difrod. Mae gan ein lliwiau Du Superior gyfraddau amsugno dŵr isel, gan leihau'r posibilrwydd y bydd eich mesuryddion manwl gywir yn rhydu wrth osod ar y platiau. Mae lliwiau'r gwenithfaen a gynigir gan ZHHIMG yn arwain at lai o lewyrch, sy'n golygu llai o straen ar y llygaid i unigolion sy'n defnyddio'r platiau. Rydym wedi dewis ein mathau o wenithfaen wrth ystyried ehangu thermol mewn ymdrech i gadw'r agwedd hon yn fach iawn.

CUSTOM APPLICATIONS
Pan fydd eich cymhwysiad yn galw am blât gyda siapiau personol, mewnosodiadau edau, slotiau neu beiriannu arall, byddwch chi eisiau dewis deunydd fel Du Jinan Du. Mae'r deunydd naturiol hwn yn cynnig anystwythder uwch, lliniaru dirgryniad rhagorol, a pheiriannu gwell.

Mae'n bwysig nodi nad yw lliw yn unig yn arwydd o rinweddau ffisegol y garreg. Yn gyffredinol, mae lliw gwenithfaen yn uniongyrchol gysylltiedig â phresenoldeb neu absenoldeb mwynau, a allai fod heb unrhyw effaith ar y rhinweddau sy'n gwneud deunydd plât arwyneb da. Mae gwenithfaen pinc, llwyd a du sy'n ardderchog ar gyfer platiau arwyneb, yn ogystal â gwenithfaen du, llwyd a phinc sy'n gwbl anaddas ar gyfer cymwysiadau manwl gywir. Nid oes gan nodweddion hanfodol gwenithfaen, fel y maent yn ymwneud â'i ddefnydd fel deunydd plât arwyneb, ddim i'w wneud â lliw, ac maent fel a ganlyn:
■ Anystwythder (gwyriad o dan lwyth - a nodir gan Fodwlws Elastigedd)
■ Caledwch
■ Dwysedd
■ Gwrthiant gwisgo
■ Sefydlogrwydd
■ Mandylledd

Rydym wedi profi llawer o ddeunyddiau gwenithfaen a'u cymharu. Yn olaf, cawsom y canlyniad, gwenithfaen du Jinan yw'r deunydd gorau rydyn ni erioed wedi'i adnabod. Mae gwenithfaen du Indiaidd a gwenithfaen De Affrica yn debyg i Wenithfaen Du Jinan, ond mae eu priodweddau ffisegol yn llai na Gwenithfaen Du Jinan. Bydd ZHHIMG yn parhau i chwilio am fwy o ddeunyddiau gwenithfaen yn y byd ac yn cymharu eu priodweddau ffisegol.

I siarad mwy am y gwenithfaen sy'n iawn ar gyfer eich prosiect, cysylltwch â niinfo@zhhimg.com.

Mae gwahanol wneuthurwyr yn defnyddio gwahanol safonau. Mae yna lawer o safonau yn y byd.
Safon DIN, ASME B89.3.7-2013 neu Fanyleb Ffederal GGG-P-463c (Platiau Arwyneb Gwenithfaen) ac yn y blaen fel sail ar gyfer eu manylebau.

A gallwn gynhyrchu plât archwilio manwl gwenithfaen yn ôl eich gofynion. Croeso i chi gysylltu â ni os ydych chi eisiau gwybod mwy o wybodaeth am fwy o safonau.

Gellir ystyried gwastadrwydd fel pob pwynt ar yr wyneb wedi'i gynnwys o fewn dau awyren gyfochrog, sef awyren y sylfaen a awyren y to. Mesuriad y pellter rhwng yr awyrennau yw gwastadrwydd cyffredinol yr wyneb. Mae gan y mesuriad gwastadrwydd hwn fel arfer oddefgarwch a gall gynnwys dynodiad gradd.

Er enghraifft, diffinnir y goddefiannau gwastadrwydd ar gyfer tair gradd safonol yn y fanyleb ffederal fel y'u pennir gan y fformiwla ganlynol:
■ Gradd Labordy AA = (40 + croeslin sgwâr/25) x .000001" (unochrog)
■ Gradd Arolygu A = Gradd Labordy AA x 2
■ Ystafell Offer Gradd B = Labordy Gradd AA x 4.

Ar gyfer platiau wyneb o faint safonol, rydym yn gwarantu goddefiannau gwastadrwydd sy'n rhagori ar ofynion y fanyleb hon. Yn ogystal â gwastadrwydd, mae ASME B89.3.7-2013 a Manyleb Ffederal GGG-P-463c yn mynd i'r afael â phynciau gan gynnwys: cywirdeb mesur ailadroddus, priodweddau deunydd gwenithfaen platiau wyneb, gorffeniad wyneb, lleoliad pwynt cynnal, anystwythder, dulliau archwilio derbyniol, gosod mewnosodiadau edau, ac ati.

Mae platiau wyneb gwenithfaen ZHHIMG a phlatiau archwilio gwenithfaen yn bodloni neu'n rhagori ar yr holl ofynion a nodir yn y fanyleb hon. Ar hyn o bryd, nid oes manyleb ddiffiniol ar gyfer platiau ongl gwenithfaen, paralelau, na sgwariau meistr.

A gallwch ddod o hyd i'r fformwlâu ar gyfer safonau eraill ynLAWRLWYTHO.

Yn gyntaf, mae'n bwysig cadw'r plât yn lân. Llwch sgraffiniol yn yr awyr yw'r ffynhonnell fwyaf o draul a rhwyg ar blât fel arfer, gan ei fod yn tueddu i ymgorffori mewn darnau gwaith ac arwynebau cyswllt mesuryddion. Yn ail, gorchuddiwch eich plât i'w amddiffyn rhag llwch a difrod. Gellir ymestyn oes traul trwy orchuddio'r plât pan nad yw'n cael ei ddefnyddio, trwy gylchdroi'r plât o bryd i'w gilydd fel nad yw un ardal yn cael ei defnyddio'n ormodol, a thrwy ddisodli padiau cyswllt dur ar fesuryddion gyda phadiau carbid. Hefyd, osgoi gosod bwyd neu ddiodydd meddal ar y plât. Sylwch fod llawer o ddiodydd meddal yn cynnwys asid carbonig neu ffosfforig, a all doddi'r mwynau meddalach a gadael pyllau bach yn yr wyneb.

Mae hyn yn dibynnu ar sut mae'r plât yn cael ei ddefnyddio. Os yn bosibl, rydym yn argymell glanhau'r plât ar ddechrau'r dydd (neu shifft gwaith) ac eto ar y diwedd. Os bydd y plât yn mynd yn fudr, yn enwedig gyda hylifau olewog neu gludiog, mae'n debyg y dylid ei lanhau ar unwaith.

Glanhewch y plât yn rheolaidd gyda glanhawr platiau wyneb hylif neu ddi-ddŵr ZHHIMG. Mae'r dewis o doddiannau glanhau yn bwysig. Os defnyddir toddydd anweddol (aseton, teneuach lacr, alcohol, ac ati) bydd yr anweddiad yn oeri'r wyneb, ac yn ei ystumio. Yn yr achos hwn, mae angen caniatáu i'r plât normaleiddio cyn ei ddefnyddio neu bydd gwallau mesur yn digwydd.

Bydd yr amser sydd ei angen i'r plât normaleiddio yn amrywio yn ôl maint y plât, a faint o oeri. Dylai awr fod yn ddigonol ar gyfer platiau llai. Efallai y bydd angen dwy awr ar gyfer platiau mwy. Os defnyddir glanhawr sy'n seiliedig ar ddŵr, bydd rhywfaint o oeri anweddol hefyd.

Bydd y plât hefyd yn cadw'r dŵr, a gallai hyn achosi i rannau metel sy'n dod i gysylltiad â'r wyneb rydu. Bydd rhai glanhawyr hefyd yn gadael gweddillion gludiog ar ôl iddynt sychu, a fydd yn denu llwch yn yr awyr, ac mewn gwirionedd yn cynyddu traul, yn hytrach na'i leihau.

Mae hyn yn dibynnu ar y defnydd a wneir o'r plât a'r amgylchedd. Rydym yn argymell bod plât newydd neu ategolion gwenithfaen manwl yn cael eu hail-raddnodi'n llawn o fewn blwyddyn i'w brynu. Os bydd y plât wyneb gwenithfaen yn cael ei ddefnyddio'n helaeth, efallai y byddai'n ddoeth byrhau'r cyfnod hwn i chwe mis. Bydd archwiliad misol am wallau mesur ailadroddus gan ddefnyddio lefel electronig, neu ddyfais debyg, yn dangos unrhyw fannau gwisgo sy'n datblygu a dim ond ychydig funudau y bydd yn eu cymryd i'w berfformio. Ar ôl pennu canlyniadau'r ail-raddnodi cyntaf, gellir ymestyn neu fyrhau'r cyfnod graddnodi fel y caniateir neu sy'n ofynnol gan eich system ansawdd fewnol.

Gallwn gynnig gwasanaeth i'ch helpu i archwilio a graddnodi'ch plât wyneb gwenithfaen.

Mae sawl achos posibl dros amrywiadau rhwng calibradiadau:

• Golchwyd yr wyneb gyda thoddiant poeth neu oer cyn calibradu, ac ni chaniatawyd digon o amser iddo normaleiddio
• Mae'r plât wedi'i gefnogi'n amhriodol
• Newid tymheredd
• Drafftiau
• Golau haul uniongyrchol neu wres ymbelydrol arall ar wyneb y plât. Gwnewch yn siŵr nad yw goleuadau uwchben yn cynhesu'r wyneb.
• Amrywiadau yn y graddiant tymheredd fertigol rhwng y gaeaf a'r haf (Os yn bosibl o gwbl, gwyddoch y tymheredd graddiant fertigol ar yr adeg y perfformir y calibradu.)
• Ni chaniatawyd digon o amser i'r plât normaleiddio ar ôl ei gludo
• Defnydd amhriodol o offer archwilio neu ddefnyddio offer heb ei galibro
• Newid arwyneb yn deillio o wisgo

Faint o fathau o dyllau sydd ar wenithfaen manwl gywir?

Slotiau ar Gydrannau Gwenithfaen Manwl

I lawer o ffatrïoedd, ystafelloedd archwilio a labordai, mae platiau wyneb gwenithfaen manwl gywir yn cael eu dibynnu ar sail ar gyfer mesur cywir. Gan fod pob mesuriad llinol yn dibynnu ar arwyneb cyfeirio cywir y cymerir y dimensiynau terfynol ohono, mae platiau wyneb yn darparu'r plân cyfeirio gorau ar gyfer archwilio a chynllunio gwaith cyn peiriannu. Maent hefyd yn seiliau delfrydol ar gyfer gwneud mesuriadau uchder a mesur arwynebau. Ymhellach, mae gradd uchel o wastadrwydd, sefydlogrwydd, ansawdd cyffredinol a chrefftwaith yn eu gwneud yn ddewis da ar gyfer gosod systemau mesur mecanyddol, electronig ac optegol soffistigedig. Ar gyfer unrhyw un o'r prosesau mesur hyn, mae'n hanfodol cadw platiau wyneb wedi'u calibro.

Repeat Measurements and Flatness

Mae gwastadrwydd ac ailadrodd mesuriadau yn hanfodol i sicrhau arwyneb manwl gywir. Gellir ystyried gwastadrwydd fel pob pwynt ar yr wyneb wedi'i gynnwys o fewn dau awyren gyfochrog, sef awyren y sylfaen a awyren y to. Mesuriad y pellter rhwng yr awyrennau yw gwastadrwydd cyffredinol yr wyneb. Mae gan y mesuriad gwastadrwydd hwn fel arfer oddefgarwch a gall gynnwys dynodiad gradd.

The flatness tolerances for three standard grades are defined in the federal specification as determined by the following formula:

Safon DIN, Safon GB, Safon ASME, safon JJS ... gwlad wahanol gyda gwahanol safiadau ...

Mwy o fanylion am y safon.

In addition to flatness, repeatability must be ensured. A repeat measurement is a measurement of local flatness areas. It is a measurement taken anywhere on the surface of a plate that will repeat within the stated tolerance. Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.

Er mwyn sicrhau bod plât arwyneb yn bodloni'r manylebau gwastadrwydd ac ailadrodd mesur, dylai gweithgynhyrchwyr platiau arwyneb gwenithfaen ddefnyddio Manyleb Ffederal GGG-P-463c fel sail ar gyfer eu manylebau. Mae'r safon hon yn mynd i'r afael â chywirdeb ailadrodd mesur, priodweddau deunydd plât arwyneb gwenithfaen, gorffeniad arwyneb, lleoliad pwynt cynnal, anystwythder, dulliau arolygu derbyniol a gosod mewnosodiadau edau.

Checking Plate Accuracy

Drwy ddilyn ychydig o ganllawiau syml, dylai buddsoddiad mewn plât wyneb gwenithfaen bara am flynyddoedd lawer. Yn dibynnu ar y defnydd o'r plât, amgylchedd y siop a'r cywirdeb gofynnol, mae amlder gwirio cywirdeb y plât wyneb yn amrywio. Rheol gyffredinol yw i blât newydd gael ei ail-raddnodi'n llawn o fewn blwyddyn i'w brynu. Os defnyddir y plât yn aml, mae'n ddoeth byrhau'r cyfnod hwn i chwe mis.

Before a surface plate has worn beyond specification for overall flatness, it will show worn or wavy posts. Monthly inspection for repeat measurement errors using a repeat reading gage will identify wear spots. A repeat reading gage is a high-precision instrument that detects local error and can be displayed on a high magnification electronic amplifier.

An effective inspection program should include regular checks with an autocollimator, providing actual calibration of overall flatness traceable to National Institute of Standards and Technology (NIST). Comprehensive calibration by the manufacturer or an independent company is necessary from time to time.

Variations Between Calibrations

Mewn rhai achosion, mae amrywiadau rhwng calibradiadau platiau arwyneb. Weithiau gall ffactorau fel newid arwyneb sy'n deillio o wisgo, defnydd anghywir o offer archwilio neu ddefnyddio offer heb ei galibro gyfrif am yr amrywiadau hyn. Y ddau ffactor mwyaf cyffredin, fodd bynnag, yw tymheredd a chefnogaeth.

One of the most important variables is temperature. For instance, the surface might have been washed with a hot or cold solution prior to calibration and not allowed sufficient time to normalize. Other causes of temperature change include drafts of cold or hot air, direct sunlight, overhead lighting or other sources of radiant heat on the surface of the plate.

There also can be variations in the vertical temperature gradient between winter and summer. In some cases, the plate is not allowed sufficient time to normalize after shipment. It is a good idea to record the vertical gradient temperature at the time the calibration is performed.

Another common cause for calibration variation is a plate that is improperly supported. A surface plate should be supported at three points, ideally located 20% of the length in from the ends of the plate. Two supports should be located 20% of the width in from the long sides, and the remaining support should be centered.

Only three points can rest solidly on anything but a precision surface. Attempting to support the plate at more than three points will cause the plate to receive its support from various combinations of three points, which will not be the same three points on which it was supported during production. This will introduce errors as the plate deflects to conform to the new support arrangement. Consider using steel stands with support beams designed to line up with the proper support points. Stands for this purpose are generally available from the surface plate manufacturer.

If the plate is properly supported, precise leveling is only necessary if an application specifies it. Leveling is not necessary to maintain the accuracy of a properly supported plate.

Extend Plate Life

Bydd dilyn ychydig o ganllawiau yn lleihau traul ar blât wyneb gwenithfaen ac yn y pen draw, yn ymestyn ei oes.

Yn gyntaf, mae'n bwysig cadw'r plât yn lân. Llwch sgraffiniol yn yr awyr fel arfer yw'r ffynhonnell fwyaf o draul a rhwyg ar blât, gan ei fod yn tueddu i ymgorffori mewn darnau gwaith ac arwynebau cyswllt mesuryddion.

It also is important to cover plates to protect it from dust and damage. Wear life can be extended by covering the plate when not in use.

Cylchdrowch y plât o bryd i'w gilydd fel nad yw un ardal yn cael ei defnyddio'n ormodol. Hefyd, argymhellir disodli padiau cyswllt dur ar fesuryddion gyda phadiau carbid.

Avoid setting food or soft drinks on the plate. Many soft drinks contain either carbonic or phosphoric acid, which can dissolve the softer minerals and leave small pits in the surface.

Where to Relap

Pan fydd angen ail-wynebu plât wyneb gwenithfaen, ystyriwch a ddylid cael y gwasanaeth hwn wedi'i gyflawni ar y safle neu yn y cyfleuster calibradu. Mae bob amser yn well cael y plât wedi'i ail-lapio yn y ffatri neu gyfleuster pwrpasol. Fodd bynnag, os nad yw'r plât wedi treulio'n rhy ddrwg, fel arfer o fewn 0.001 modfedd i'r goddefgarwch gofynnol, gellir ei ail-wynebu ar y safle. Os yw plât wedi treulio i'r pwynt lle mae fwy na 0.001 modfedd y tu allan i'r goddefgarwch, neu os yw wedi'i bylu neu ei nicio'n ddrwg, yna dylid ei anfon i'r ffatri i'w falu cyn ei ail-lapio.

A calibration facility has the equipment and factory setting providing the optimum conditions for proper plate calibration and rework if necessary.

Dylid bod yn ofalus iawn wrth ddewis technegydd calibradu ac ail-wynebu ar y safle. Gofynnwch am achrediad a gwiriwch fod gan yr offer y bydd y technegydd yn ei ddefnyddio galibradu olrheiniadwy. Mae profiad hefyd yn ffactor pwysig, gan ei fod yn cymryd blynyddoedd lawer i ddysgu sut i lapio gwenithfaen manwl gywir.

Critical measurements start with a precision granite surface plate as a baseline. By ensuring a reliable reference by using a properly calibrated surface plate, manufacturers have one of the essential tools for reliable measurements and better quality parts.Q

Checklist for Calibration Variations

1. Golchwyd yr wyneb gyda thoddiant poeth neu oer cyn calibradu ac ni chaniatawyd digon o amser iddo normaleiddio.

2. Mae'r plât wedi'i gefnogi'n amhriodol.

3. Newid tymheredd.

4. Drafftiau.

5. Golau haul uniongyrchol neu wres ymbelydrol arall ar wyneb y plât. Gwnewch yn siŵr nad yw goleuadau uwchben yn cynhesu'r wyneb.

6. Amrywiadau yn y graddiant tymheredd fertigol rhwng y gaeaf a'r haf. Os yn bosibl o gwbl, gwyddoch y tymheredd graddiant fertigol ar yr adeg y perfformir y calibradu.

7. Ni chaniatawyd digon o amser i'r plât normaleiddio ar ôl ei gludo.

8. Defnydd amhriodol o offer archwilio neu ddefnyddio offer heb ei galibro.

9. Newid arwyneb yn deillio o wisgo.

Tech Tips

• Gan fod pob mesuriad llinol yn dibynnu ar arwyneb cyfeirio cywir y cymerir y dimensiynau terfynol ohono, mae platiau arwyneb yn darparu'r plân cyfeirio gorau ar gyfer archwilio a chynllunio gwaith cyn peiriannu.
• Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.
• Dylai rhaglen arolygu effeithiol gynnwys gwiriadau rheolaidd gydag awtocolimator, gan ddarparu calibradu gwirioneddol o wastadrwydd cyffredinol y gellir ei olrhain i'r Awdurdod Arolygu Cenedlaethol.

Ymhlith y gronynnau mwynau sy'n ffurfio gwenithfaen, mae mwy na 90% yn ffelsbar a chwarts, a ffelsbar yw'r mwyaf ohonynt. Mae'r ffelsbar yn aml yn wyn, llwyd, a choch fel y cnawd, ac mae'r cwarts yn bennaf yn ddi-liw neu'n wyn llwydaidd, sy'n ffurfio lliw sylfaenol y gwenithfaen. Mae ffelsbar a chwarts yn fwynau caled, ac mae'n anodd eu symud â chyllell ddur. O ran y smotiau tywyll yn y gwenithfaen, yn bennaf mica du, mae yna rai mwynau eraill. Er bod biotit yn gymharol feddal, nid yw ei allu i wrthsefyll straen yn wan, ac ar yr un pryd mae ganddynt ychydig bach mewn gwenithfaen, yn aml llai na 10%. Dyma'r cyflwr deunydd lle mae gwenithfaen yn arbennig o gryf.

Rheswm arall pam mae gwenithfaen yn gryf yw bod ei ronynnau mwynau wedi'u rhwymo'n dynn i'w gilydd ac wedi'u hymgorffori yn ei gilydd. Yn aml, mae'r mandyllau'n cyfrif am lai nag 1% o gyfanswm cyfaint y graig. Mae hyn yn rhoi'r gallu i'r gwenithfaen wrthsefyll pwysau cryf ac nid yw lleithder yn treiddio iddo'n hawdd.

Mae cydrannau gwenithfaen wedi'u gwneud o garreg heb unrhyw wrthwynebiad rhwd, asid ac alcali, gwrthiant gwisgo da a bywyd gwasanaeth hir, dim cynnal a chadw arbennig. Defnyddir cydrannau manwl gwenithfaen yn bennaf yn offer y diwydiant peiriannau. Felly, fe'u gelwir yn gydrannau manwl gwenithfaen neu gydrannau gwenithfaen. Mae nodweddion cydrannau manwl gwenithfaen yr un fath yn y bôn â nodweddion llwyfannau gwenithfaen. Cyflwyniad i offer a mesur cydrannau manwl gwenithfaen: Mae technoleg peiriannu manwl a micro-beiriannu yn gyfeiriadau datblygu pwysig yn y diwydiant gweithgynhyrchu peiriannau, ac maent wedi dod yn ddangosydd pwysig i fesur lefel uwch-dechnoleg. Mae datblygu technoleg arloesol a'r diwydiant amddiffyn yn anwahanadwy oddi wrth beiriannu manwl a thechnoleg micro-beiriannu. Gellir llithro cydrannau gwenithfaen yn llyfn yn y mesuriad, heb farweidd-dra. Mesur arwyneb gwaith, nid yw crafiadau cyffredinol yn effeithio ar gywirdeb mesur. Mae angen dylunio a chynhyrchu cydrannau gwenithfaen yn unol â gofynion yr ochr galw.

Maes cais:

Fel y gwyddom i gyd, mae mwy a mwy o beiriannau ac offer yn dewis cydrannau gwenithfaen manwl gywir.

Defnyddir cydrannau gwenithfaen ar gyfer symudiad deinamig, moduron llinol, cmm, cnc, peiriant laser...

croeso i chi gysylltu â ni am ragor o wybodaeth.

Mae dyfeisiau mesur gwenithfaen a chydrannau mecanyddol gwenithfaen wedi'u gwneud o wenithfaen Jinan Black o ansawdd uchel. Oherwydd eu cywirdeb uchel, eu hyd hir, eu sefydlogrwydd da a'u gwrthwynebiad cyrydiad, maent wedi cael eu defnyddio fwyfwy mewn archwilio cynhyrchion diwydiant modern a meysydd gwyddonol fel awyrofod mecanyddol ac ymchwiliadau gwyddonol.

Manteision

----Ddwywaith mor galed â haearn bwrw;

----Mae newidiadau lleiaf mewn dimensiwn oherwydd newidiadau tymheredd;

----Yn rhydd o wasgu, felly nid oes ymyrraeth â gwaith;

----Yn rhydd o fwrlwm neu ymwthiadau oherwydd y strwythur grawn mân a'r gludiogrwydd dibwys, sy'n sicrhau'r radd uchel o wastadrwydd dros oes gwasanaeth hir ac nad yw'n achosi unrhyw ddifrod i rannau neu offerynnau eraill;

----Gweithrediad di-drafferth i'w ddefnyddio gyda deunyddiau magnetig;

---- Bywyd hir a di-rwd, gan arwain at gostau cynnal a chadw isel.

Mae'r platiau wyneb gwenithfaen manwl gywir wedi'u lapio'n fanwl gywir i safon uchel o wastadrwydd i sicrhau cywirdeb ac fe'u defnyddir fel sylfaen ar gyfer gosod systemau mesur mecanyddol, electronig ac optegol soffistigedig.

Rhai o nodweddion unigryw'r plât wyneb gwenithfaen:

Unffurfiaeth mewn Caledwch;

Amodau cywir o dan lwyth;

Amsugnol Dirgryniad;

Hawdd i'w Lanhau;

Gwrthsefyll Lapio;

Mandylledd Isel;

Di-sgraffinio;

Di-fagnetig

Manteision Plât Arwyneb Gwenithfaen

First, the rock after a long period of natural aging, uniform structure, coefficient minimum, the internal stress completely disappear, not deformed, so the precision is high.

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Precision Granite Base Can Improve Machine Tool Performances

Requirements are constantly increasing in mechanical engineering in general and in machine tool construction in particular. Achieving maximum precision and performance values without increasing costs are constant challenges to being competitive. The machine tool bed is a decisive factor here. Therefore, more and more machine tool manufacturers are relying on granite. Due to its physical parameters, it offers clear advantages that cannot be achieved with steel or polymer concrete.

Granite is a so-called volcanic deep rock and has a very dense and homogeneous structure with an extremely low coefficient of expansion, low thermal conductivity and high vibration damping.

Below you will discover why the common opinion that granite is mainly only suitable as machine base for high-end coordinate measuring machines is long outdated and why this natural material as a machine tool base is a very advantageous alternative to steel or cast iron even for high-precision machine tools.

We can manufacture granite components for dynamic motion, granite components for linear motors, granite components for ndt, granite components for xray, granite components for cmm, granite components for cnc, granite precision for laser, granite components for aerospace, granite components for precision stages...

High Added Value Without Additional Costs
The increasing use of granite in mechanical engineering is not so much due to the massive increase in the price of steel. Rather, it is because the added value for the machine tool achieved with a machine bed made of granite is possible at very little or no extra cost. This is proven by cost comparisons of well-known machine tool manufacturers in Germany and Europe.

The considerable gain in thermodynamic stability, vibration damping and long-term precision made possible by granite cannot be achieved with a cast iron or steel bed, or only at relatively high cost. For example, thermal errors can account for up to 75% of the total error of a machine, with compensation often attempted for by software – with moderate success. Due to its low thermal conductivity, granite is the better foundation for long-term precision.

With a tolerance of 1 μm, granite easily meets the flatness requirements according to DIN 876 for the degree of accuracy 00. With a value of 6 on the hardness scale 1 to 10, it is extremely hard, and with its specific weight of 2.8g/cm³ it almost reaches the value of aluminium. This also results in additional advantages such as higher feed rates, higher axis accelerations and an extension of the tool life for cutting machine tools. Thus, the change from a cast bed to a granite machine bed moves the machine tool in question into the high-end class in terms of precision and performance – at no extra cost.

Granite’s Improved Ecological Footprint
In contrast to materials such as steel or cast iron, natural stone does not have to be produced with a great deal of energy and using additives. Only relatively small amounts of energy are required for quarrying and surface treatment. This results in a superior ecological footprint, which even at the end of a machine’s life surpasses that of steel as a material. The granite bed can be the basis for a new machine or be used for completely different purposes such as shredding for road construction.

Nor are there any shortages of resources for granite. It is a deep rock formed from magma within the earth’s crust. It has ‘matured’ for millions of years and is available in very large quantities as a natural resource on almost all continents, including all of Europe.

Conclusion: The numerous demonstrable advantages of granite compared to steel or cast iron justify the increasing willingness of mechanical engineers to use this natural material as a foundation for high-precision, high-performance machine tools. Detailed information about granite properties, which are advantageous for machine tools and mechanical engineering, can be found in this further article.

A repeat measurement is a measurement of local flatness areas. The Repeat Measurement specification states that a measurement taken anywhere on the surface of a plate will repeat within the stated tolerance. Controlling local area flatness tighter than overall flatness guarantees a gradual change in surface flatness profile thereby minimizing local errors.

Most manufacturers, including imported brands, adhere to the Federal Specification of overall flatness tolerances but many overlook the repeat measurements. Many of the low value or budget plates available in the market today will not guarantee repeat measurements. A manufacturer who does not guarantee repeat measurements is NOT producing plates that meet the requirements of ASME B89.3.7-2013 or Federal Specification GGG-P-463c, or DIN 876, GB, JJS...

Both are critical to ensure a precision surface for accurate measurements. Flatness specification alone is not sufficient to guarantee measurement accuracy. Take as an example, a 36 X 48 Inspection Grade A surface plate, which meets ONLY the flatness specification of .000300". If the piece being checked bridges several peaks, and the gage being used is in a low spot, the measurement error could be the full tolerance in one area, 000300"! Actually, it can be much higher if the gage is resting on the slope of an incline.

Errors of .000600"-.000800" are possible, depending upon the severity of the slope, and the arm length of the gage being used. If this plate had a Repeat Measurement specification of .000050"F.I.R. then the measurement error would be less than .000050" regardless of where the measurement is taken on the plate. Another problem, which usually arises when an untrained technician attempts to resurface a plate on-site, is the use of Repeat Measurements alone to certify a plate.

The instruments that are used to verify repeatability are NOT designed to check overall flatness. When set to zero on a perfectly curved surface, they will continue to read zero, whether that surface is perfectly flat or perfectly concave or convex 1/2"! They simply verify the uniformity of the surface, not the flatness. Only a plate that meets both the flatness specification AND the repeat measurement specification truly meets the requirements of ASME B89.3.7-2013  or Federal Specification GGG-P-463c.

Ask us about or flatness specification and repeat measurement promise by calling +86 19969991659 or emailing INFO@ZHHIMG.COM

Yes, but they can only be guaranteed for a specific vertical temperature gradient. The effects of thermal expansion on the plate could easily cause a change in accuracy greater than the tolerance if there is a change in the gradient. In some cases, if the tolerance is tight enough, the heat absorbed from overhead lighting can cause enough of a gradient change over several hours.

Granite has a coefficient of thermal expansion of approximately .0000035 inches per inch per 1°F. As an example: A 36" x 48" x 8" surface plate has an accuracy of .000075" (1/2 of Grade AA) at a gradient of 0°F, the top and bottom are the same temperature. If the top of the plate warms up to the point where it is 1°F warmer than the bottom, the accuracy would change to .000275" convex ! Therefore, ordering a plate with a tolerance tighter than Laboratory Grade AA should only be considered if there is adequate climate control.

A surface plate should be supported at 3 points, ideally located 20% of the length in from the ends of the plate. Two supports should be located 20% of the width in from the long sides, and the remaining support should be centered. Only 3 points can rest solidly on anything but a precision surface.

The plate should be supported at these points during production, and it should be supported only at these three points while in use. Attempting to support the plate at more than three points will cause the plate to receive its support from various combinations of three points, which will not be the same 3 points on which it was supported during production. This will introduce errors as the plate deflects to conform to the new support arrangement. All zhhimg steel stands have support beams designed to line up with the proper support points.

If the plate is properly supported, precise leveling is only necessary if your application calls for it. Leveling is not necessary to maintain the accuracy of a properly supported plate.

Why Choose Granite for Machine Bases and Metrology Components?

The answer is 'yes' for almost every application. The advantages of granite include: No rust or corrosion, almost immune to warping, no compensating hump when nicked, longer wear life, smoother action, greater precision, virtually non-magnetic, low co-efficient of thermal expansion, and low maintenance cost.

Granite is a type of igneous rock quarried for its extreme strength, density, durability, and resistance to corrosion. But granite is also very versatile– it’s not just for squares and rectangles! In fact, Starrett Tru-Stone confidently works with granite components engineered in shapes, angles, and curves of all variations on a regular basis—with excellent outcomes.

Through our state of the art processing, cut surfaces can be exceptionally flat. These qualities make granite the ideal material to create custom-size and custom-design machine bases and metrology components. Granite is:

machineable
precisely flat when cut and finished
rust resistant
durable
long lasting
Granite components are also easy to clean. When creating custom designs, be sure to choose granite for its superior benefits.

STANDARDS / HIGH WEAR APPLICATIONS
The granite utilized by ZhongHui for our standard surface plate products has high quartz content, which provides greater resistance to wear and damage. Our Superior Black and Crystal Pink colors have low water absorption rates, minimizing the possibility of your precision gages rusting while setting on the plates. The colors of granite offered by ZhongHui result in less glare, which means less eyestrain for individuals using the plates. We have chosen our granite types while considering thermal expansion in an effort to keep this aspect minimal.

CUSTOM APPLICATIONS
When your application calls for a plate with custom shapes, threaded inserts, slots or other machining, you’ll want to select a material like Black Diabase. This natural material offers superior stiffness, excellent vibration dampening, and improved machinability.

Yes, if they are not too badly worn. Our factory setting and equipment allow the optimum conditions for proper plate calibration and rework if necessary. Generally, if a plate is within .001" of the required tolerance, it can be resurfaced on-site. If a plate is worn to the point where it is more than .001" out of tolerance, or if it is badly pitted or nicked, then it will need to be sent to the factory for grinding prior to relapping.

Great care should be exercised in selecting an on-site calibration and resurfacing technician. We urge you to use caution in selecting your calibration service. Ask for accreditation and verify the equipment that the technician will use has a National Inspection Institution traceable calibration. It takes many years to learn how to properly lap precision granite.

ZhongHui provides quick turn-around on calibrations performed in our factory. Send your plates in for calibration if possible. Your quality and reputation depend on the accuracy of your measurement instruments including surface plates!

Our black surface plates have a significantly higher density and are up to three times as stiff. Therefore, a plate made of the black does not need to be as thick as a granite plate of the same size to have equal or greater resistance to deflection. Reduced thickness means less weight and lower shipping costs.

Beware of others who use lower quality black granite in the same thickness. As stated above, properties of granite, like wood or metal, vary by material and color, and is not an accurate predictor of stiffness, hardness, or wear resistance. In fact, many types of black granite and diabase are very soft and not suitable for surface plate applications.

No. The specialized equipment and training necessary to rework these items requires that they be returned to the factory for calibration and rework.

Yes. Ceramic and granite have similar characteristics, and the methods used to calibrate and lap granite can be used with ceramic items as well. Ceramics are more difficult to lap than granite resulting in a higher cost.

Yes, provided that the inserts are recessed below the surface. If steel inserts are flush with, or above the surface plane, they must be spot-faced down before the plate can be lapped. If required, we can provide that service.

Yes. Steel inserts with the desired thread (English or metric) can be epoxy bonded into the plate at the desired locations. ZhongHui uses CNC machines to provide the tightest insert locations within +/- 0.005”. For less critical inserts, our locational tolerance for threaded inserts is ±.060". Other options include steel T-Bars and dovetail slots machined directly into the granite.

Inserts that are properly bonded using high strength epoxy and good workmanship will withstand a great deal of torsional and shear force. In a recent test, using 3/8"-16 threaded inserts, an independent testing laboratory measured the force required to pull an epoxy-bonded insert from a surface plate. Ten plates were tested. Out of these ten, in nine cases, the granite fractured first. The average load at the point of failure was 10,020 lbs. for gray granite and 12,310 lbs. for black. In the single case where an insert pulled free of the plate, the load at the point of failure was 12,990 lbs.! If a work piece forms a bridge across the insert and extreme torque is applied, it is possible to generate enough force to fracture the granite. Partially for this reason, ZhongHui gives guidelines for the maximum safe torque that can be applied the epoxy bonded inserts: https://www.zhhimg.com/standard-thread-inserts-product/

Yes, but only at our factory. At our plant, we can restore almost any plate to 'like-new' condition, usually for less than half the cost of replacing it. Damaged edges can be cosmetically patched, deep grooves, nicks, and pits can be ground out, and the attached supports can be replaced. In addition, we can modify your plate to increase its versatility by adding solid or threaded steel inserts and cutting slots or clamping lips, per your specifications.

Why Choose Granite?
Granite is a type of igneous rock formed in the Earth millions of years ago. The composition of igneous rock contained many minerals such as quartz that is extremely hard and wear-resistant. In addition to hardness and wear resistance granite has approximately half the coefficient of expansion as cast iron. As its volumetric weight is approximately one third that of cast iron, granite is easier to manoeuvre.

For machine bases and metrology components, black granite is the colour most used. Black granite has a higher percentage of quartz than other colours and is, therefore, the hardest wearing.

Granite is cost-effective, and cut surfaces can be exceptionally flat. Not only can it be hand lapped to achieve extremes of accuracy, but re-conditioning can be performed without moving the plate or table off-site. It is entirely a hand lapping operation and generally costs much less than re-conditioning a cast iron alternative.

These qualities make granite the ideal material to create custom-size and custom-design machine bases and metrology components such as the granite surface plate.

ZhongHui produces bespoke granite products that are created to support specific measurement requirements. These bespoke items vary from straight edges to tri squares. Due to the versatile nature of granite, the components can be produced to any size required; they are hard wearing and long-lasting.

Advantages of Granite Surface Plates
The importance of measuring on an even surface was established by British inventor Henry Maudsley in the 1800s. As a machine tool innovator, he determined that consistent production of parts required a solid surface for reliable measurements.

The industrial revolution created a demand for measuring surfaces, so engineering company Crown Windley created manufacturing standards. The standards for surface plates were first set by Crown in 1904 using metal. As the demand and cost for metal increased, alternative materials for the measuring surface were investigated.

In America, monument creator Wallace Herman established that black granite was an excellent surface plate material alternative to metal. As granite is non-magnetic and doesn’t rust, it soon became the preferred measuring surface.

A granite surface plate is an essential investment for laboratories and test facilities. A granite surface plate of 600 x 600 mm can be mounted on a support stand. The stands provide a working height of 34” (0.86m) with five adjustable points for levelling.

For reliable and consistent measurement results, a granite surface plate is crucial. As the surface is a smooth and stable plane, it enables instruments to be carefully manipulated.

The main advantages of granite surface plates are:

• Non-reflective
• Resistant to chemicals and corrosion
• Low coefficient of expansion compared with cart iron so less affected by temperature change
• Naturally rigid and hard-wearing
• The plane of the surface is unaffected if scratched
• Will not rust
• Non-magnetic
• Easy to clean and maintain
• Calibration and resurfacing can be done onsite
• Suitable for drilling for threaded support inserts
• High vibration damping

For many shops, inspection rooms and laboratories, precision granite surface plates are relied on as the basis for accurate measurement. Because every linear measurement depends on an accurate reference surface from which final dimensions are taken, surface plates provide the best reference plane for work inspection and layout prior to machining. They also are ideal bases for making height measurements and gaging surfaces. Further, a high degree of flatness, stability, overall quality and workmanship make them a good choice for mounting sophisticated mechanical, electronic and optical gaging systems. For any of these measurement processes, it is imperative to keep surface plates calibrated.

Repeat Measurements and Flatness
Both flatness and repeat measurements are critical to ensure a precision surface. Flatness can be considered as all points on the surface being contained within two parallel planes, the base plane and the roof plane. The measurement of distance between the planes is the overall flatness of the surface. This flatness measurement commonly carries a tolerance and may include a grade designation.

The flatness tolerances for three standard grades are defined in the federal specification as determined by the following formula:
Laboratory Grade AA = (40 + diagonal² / 25) x 0.000001 inch (unilateral)
Inspection Grade A = Laboratory Grade AA x 2
Tool Room Grade B = Laboratory Grade AA x 4

In addition to flatness, repeatability must be ensured. A repeat measurement is a measurement of local flatness areas. It is a measurement taken anywhere on the surface of a plate that will repeat within the stated tolerance. Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.

To ensure a surface plate meets both the flatness and repeat measurement specifications, manufacturers of granite surface plates should use Federal Specification GGG-P-463c as a basis for their specifications. This standard addresses repeat measurement accuracy, material properties of surface plate granites, surface finish, support point location, stiffness, acceptable methods of inspection and installation of threaded inserts.

Before a surface plate has worn beyond specification for overall flatness, it will show worn or wavy posts. Monthly inspection for repeat measurement errors using a repeat reading gage will identify wear spots. A repeat reading gage is a high-precision instrument that detects local error and can be displayed on a high magnification electronic amplifier.

Checking Plate Accuracy
By following a few simple guidelines, an investment in a granite surface plate should last for many years. Depending on plate usage, shop environment and required accuracy, frequency of checking the surface plate accuracy varies. A general rule of thumb is for a new plate to receive a full recalibration within one year of purchase. If the plate is used frequently, it is advisable to shorten this interval to six months.

Before a surface plate has worn beyond specification for overall flatness, it will show worn or wavy posts. Monthly inspection for repeat measurement errors using a repeat reading gage will identify wear spots. A repeat reading gage is a high-precision instrument that detects local error and can be displayed on a high magnification electronic amplifier.

An effective inspection program should include regular checks with an autocollimator, providing actual calibration of overall flatness traceable to National Institute of Standards and Technology (NIST). Comprehensive calibration by the manufacturer or an independent company is necessary from time to time.

Variations Between Calibrations
In some cases, there are variations between surface plate calibrations. Sometimes factors such as surface change resulting from wear, incorrect use of inspection equipment or use of noncalibrated equipment can account for these variations. The two most common factors, however, are temperature and support.

One of the most important variables is temperature. For instance, the surface might have been washed with a hot or cold solution prior to calibration and not allowed sufficient time to normalize. Other causes of temperature change include drafts of cold or hot air, direct sunlight, overhead lighting or other sources of radiant heat on the surface of the plate.

There also can be variations in the vertical temperature gradient between winter and summer. In some cases, the plate is not allowed sufficient time to normalize after shipment. It is a good idea to record the vertical gradient temperature at the time the calibration is performed.

Another common cause for calibration variation is a plate that is improperly supported. A surface plate should be supported at three points, ideally located 20% of the length in from the ends of the plate. Two supports should be located 20% of the width in from the long sides, and the remaining support should be centered.

Only three points can rest solidly on anything but a precision surface. Attempting to support the plate at more than three points will cause the plate to receive its support from various combinations of three points, which will not be the same three points on which it was supported during production. This will introduce errors as the plate deflects to conform to the new support arrangement. Consider using steel stands with support beams designed to line up with the proper support points. Stands for this purpose are generally available from the surface plate manufacturer.

If the plate is properly supported, precise leveling is only necessary if an application specifies it. Leveling is not necessary to maintain the accuracy of a properly supported plate.

It is important to keep the plate clean. Airborne abrasive dust is usually the greatest source of wear and tear on a plate, as it tends to embed in workpieces and the contact surfaces of gages. Cover plates to protect them from dust and damage. Wear life can be extended by covering the plate when not in use.

Extend Plate Life
Following a few guidelines will reduce wear on a granite surface plate and ultimately, extend its life.

First, it is important to keep the plate clean. Airborne abrasive dust is usually the greatest source of wear and tear on a plate, as it tends to embed in workpieces and the contact surfaces of gages.

It also is important to cover plates to protect it from dust and damage. Wear life can be extended by covering the plate when not in use.

Rotate the plate periodically so that a single area does not receive excessive use. Also, it is recommended to replace steel contact pads on gaging with carbide pads.

Avoid setting food or soft drinks on the plate. Many soft drinks contain either carbonic or phosphoric acid, which can dissolve the softer minerals and leave small pits in the surface.

Where to Relap
When a granite surface plate needs re-surfacing, consider whether to have this service performed on-site or at the calibration facility. It is always preferable to have the plate relapped at the factory or a dedicated facility. If, however, the plate is not too badly worn, generally within 0.001 inch of the required tolerance, it can be resurfaced on-site. If a plate is worn to the point where it is more than 0.001 inch out of tolerance, or if it is badly pitted or nicked, then it should be sent to the factory for grinding prior to relapping.

A calibration facility has the equipment and factory setting providing the optimum conditions for proper plate calibration and rework if necessary.

Great care should be exercised in selecting an on-site calibration and resurfacing technician. Ask for accreditation and verify the equipment that the technician will use has a NIST-traceable calibration. Experience also is an important factor, as it takes many years to learn how to correctly lap precision granite.

Critical measurements start with a precision granite surface plate as a baseline. By ensuring a reliable reference by using a properly calibrated surface plate, manufacturers have one of the essential tools for reliable measurements and better quality parts.

Checklist for Calibration Variations

1. The surface was washed with a hot or cold solution prior to calibration and was not allowed sufficient time to normalize.
2. The plate is improperly supported.
3. Temperature change.
4. Drafts.
5. Direct sunlight or other radiant heat on the surface of the plate. Be sure that overhead lighting is not heating the surface.
6. Variations in the vertical temperature gradient between winter and summer. If at all possible, know the vertical gradient temperature at the time the calibration is performed.
7. Plate not allowed sufficient time to normalize after shipment.
8. Improper use of inspection equipment or use of noncalibrated equipment.
9. Surface change resulting from wear.

Tech Tips
Because every linear measurement depends on an accurate reference surface from which final dimensions are taken, surface plates provide the best reference plane for work inspection and layout prior to machining.

Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.