hinge & glass clamp

Terms of delivery:

1. Definition and scope

1.1Investmentcastingisaprocess by which a high surface quality can bemanufacturedthroughtheformation of dimensionally accurate casting.Thepatternsproduced byinjection
moulding are heat disposable and aremelted outaftermanufacture of the ceramic moulds. The ceramic mouldsaredestroyedafter casting. For this reason, both the pattern andthemoulds aredesignated lost using this method. Casting usuallytakesplace into hotmoulds.

1.2 Metals and nickel-based alloys can be used for investment casting.

1.3Thistechnicalmemorandumdoes not apply precious metals cast using thedewaxingmethod,toproductsof the jewellery industry,dentallaboratories or toart casting.

2. Purpose

2.1Thistechnicalmemorandumdefines dimensional tolerances, specifiesmachiningallowances andsurface roughness corresponding to the start ofthe art inthe field ofinvestment casting. It serves as a basis foroptimumeconomic cooperationbetween investment casting suppliers andbuyers.

2.2Thespecificationsmentionedhererefer to sand blasted preserved or pickledsurfaces intheirdelivered condition. Exception must be agreedwhere work processesareinvolved
which alter the dimensional tolerances.

2.3Unlessotherwiseagreed,initialsamples are supplied for first-timeorders.These are usedto permitconcrete mutual agreement betweensupplier andpurchaser.Initial samplesmust be appraised by thebuyer,followed by awritten release to thefoundry for seriesproduction.Deviationacknowledged by the releaseorwith positiveappraisal of theinitialsamples are binding for theproduction processand must beenteredintothe (casting) drawing.

3. Dimensional accuracy

3.1 Contraction and shrinkage
Duringthesolidificationandcooling of cast metals, a contraction ofthevolumenaturally occurs asaresult of shrinkage. Otherfactorsinfluencing the production ofinstrument
castingscan resultfromtheshrinkage of the lost patternand the expansion of mouldsduringheating. The sum of these influencingfactors istakenintoconsideration in the shrinkage
allowance duringthemanufacture ofinjection moulds. The shrinkage allowance is basedonexperiencevalues,depending on the contour of the casting, theceramicshell andthe casting materials, as well as the castingtechniques usedin theindividual foundries.

3.2 Reference planes and reference points
Drawingusedinthe manufacture of casting must be gauged systematicallyusingreferenceorlocating points in order to ensure that dimensionalchecksandsubsequentmachining are in agreement. Reference points mustbedeterminedright fromthe early design stage and coordinatedbetweenthezero positionof thereference planes is precisely defined bymeans ofthe referencepointdimensions. All reference points must bearranged insuch a way thattheyare not removed or altered during thesubsequentmachiningprocess.Reference points should be positioned onthe outsidesurfaces oftheinvestment casting.They may take the form ofraised orreferencepointsare beneficial when dealing with castingswithrestricted shapeandposition tolerances. When determining thereferencepoints, attentionshould be paid to ensuring that they do notfall inthe area of asprue.In case of complex shaping,it is possible inthisway to position thecasting precisely by(pre-)machining thelocatingpoints.

3.3 Over definition
According to DIN 406, overde finition must be avoided. Wall thicknesses must always be specified.

3.4 Mould and draught angles
Mould and draught angles are not necessary as a general
rule.Exceptionstothisfor reason of mould making or casting necessity must beagreedbetweenthe investment casting supplier and the buyer.

4. Dimensional tolerances

4.1 Linear dimensional tolerances
Achievable dimensional tolerances on investment casting are dependent on the following factors:
Casting material
Dimensions and shape of the casting
Validity of the accuracy grade

4.1.2. Dimensions and shape of the casting
Theachievableaccuracylevelof the rated dimensions of an investmentcasting dependson thegreatest dimension and the shape of thecasting.If therateddimension(GTA)exceeds the rated dimension rangeindicated foracertainaccuracy level,the overall tolerance of thecasting must betolerancedat the accuracy level (greatest tolerancefield). Deviationoutside theaccuracy level must be agreed between thesupplier andthebuyer.

Note: The technical info above are incomplete. Please contact us for more information.

Our Precision Investment Casting Technology has been applied in theproduction of:

A high standard of surface quality

Low material allowance on surfacesto be machined

Facility for complex shaped innercontours due to the use of ceramic cores

A high degree of dimensional accuracy due to elimination of the mould parting line usually responsible forcasting imprecision

Hardly any restrictions in terms of materials

Almost unlimited scope for the shaping of castings

The investment casting technique is characterized by

Summary

Generallyspeaking,theinvestmentcasting technique is used for small pieceweights of between1g and 10kg. Largerwork-pieces up to 150 kg are alsopossible.

Piece weights

Thecastingareproduced without any trace of flash, and with anexcellentsurfacefinish.In many cases-expect for producing the requiredseatdimensionsthere isno need for a follow-on machining process.

Surface quality

Allcastablematerialscan be processed using this method. Investmentcasting isparticularlysuitable for use with materials unsuited tomachining.

Material selection

Fullservicemanufacturing of investment castings, including machining,heattreating,passivation, plating, polishing,and painting.

We offer stainless steel, carbon or alloy steel casting made by investment casting in accordance with customer's design(OEM).

Material: 304
Finish: Sand polishing, mirror polishing
Process: investment casting and machining