dave charbauski caterpillar inc. (retired) · • finish stock • amount can vary with material...

www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc

What’s Driving the Cost of

Your Casting?

Dave Charbauski

Caterpillar Inc. (Retired)

http://www.afsinc.org/


Personal Profile

Current: Casting Quality and Sourcing Consultant

Experience: 22 Years at Caterpillar • Purchasing & Supplier Quality

17 Years in Foundry Management• Iron, Steel & Nonferrous Castings



Target Cost:X

Has This Ever Happened To You?



Target Cost:X

Supplier A + 45%

Supplier B + 55%

Supplier C + 40%

Quotes Received




Target Cost:X

Supplier A + 45%

Supplier B + 55%

Supplier C + 40%

Quotes Received

?




What do you do next?

Options

1. Find a new supply base




Options


2. Go into the Foundry business yourself




Options



3. Investigate your design for cost drivers




Options



3. Investigate your design for cost drivers

Why should I look at the design?



Design 5%

Material 50%

Labor 15%

Overhead 30%

Initial Effect

Design Impact on Product Cost Over Time



Design 5%

Material 50%

Labor 15%

Overhead 30%

Initial Effect Long Term Effect

Design 70%

Material 20%

Labor 5%Overhead 5%




Design 5%

Material 50%

Labor 15%

Overhead 30%

Initial Effect Long Term Effect

Design 70%

Material 20%

Labor 5%Overhead 5%


Potential Casting Impacts

• Higher Scrap Rates

• Increased Rework

• Delivery Problems

• Increased Costs



Reality Check

Does the part fit the foundry?



Reality Check


Metal Type• Standard grade or unique chemistry?



Reality Check



• Would changing to a standard grade meet your requirements?



Reality Check



• Would changing to a standard grade meet your requirements?• Could a lower cost material be utilized?



Reality Check



• Would changing to a standard grade meet your requirements?• Could a lower cost material be utilized?

• Commonly poured or periodically scheduled?



Reality Check


Casting Weight and Size• How well does your casting fit within the foundry’s weight

and size parameters?



Reality Check



and size parameters?• Being on either end of the spectrum can be costly



Reality Check




• Smaller/lighter castings may experience higher levels of scrap due to shakeout damage.



Reality Check




• Smaller/lighter castings may experience higher levels of scrap due to shakeout damage.

• Larger/heavier castings may require extended cooling time causing a slow down on an automated line.



Reality Check


Annual Volume• How many pieces do you plan on buying per year?



Reality Check



• Small lot sizes can be difficult in a high production foundry.



Reality Check




• How many orders per year?



Reality Check




• How many orders per year?

• Consult with your foundry to determine if your volume is considered low, medium, or high.



OK - Everything fits! What’s next?



OK - Everything fits! What’s next?

Time to dig deeper into the casting design to identify

cost drivers



Draft angles and finish stock allowance• Draft

• Excess draft can add weight• Insufficient draft can increase scrap and rework

• Most foundries need 1 to 2 degrees



Draft angles and finish stock allowance• Draft

• Excess draft can add weight• Insufficient draft can increase scrap and rework

• Most foundries need 1 to 2 degrees

• Finish Stock• Amount can vary with material type, casting size, and molding

process• Excess stock adds weight and increases machining costs• Insufficient stock can shorten insert life and increase scrap due to

tool breakage and non clean-up



Parting lines• Flat, straight partings lines are a best practice



Parting lines• Flat, straight partings lines are a best practice• Offset parting lines are common, but…

• Can increase pattern cost• Are more likely to produce parting fins• Can cause mold compaction issues



Parting lines• Flat, straight partings lines are a best practice• Offset parting lines are common, but…

• Can increase pattern cost• Are more likely to produce parting fins• Can cause mold compaction issues

• Can you minimize the effect of the parting line?



Cores• Look for ways to minimize or eliminate cores



Cores• Look for ways to minimize or eliminate cores• Can you incorporate several cores into one?

• Be aware of the assembly cost• Make sure the assembly is robust



Cores• Long cores may require chaplets for support

• Cost for chaplet, placement, and finishing• Potential for increased scrap rate



Section Thickness• Thin sections

• Can be susceptible to misrun and cracking



Section Thickness• Thin sections

• Can be susceptible to misrun and cracking

• Thick sections• May be prone to shrinkage problems

• Isolated heavy sections should be avoided



Section Thickness• Variations in wall thickness can lead to higher scrap rates



Section Thickness• Variations in wall thickness can lead to higher scrap rates• Transition design

• Abrupt transitions are stress raisers



Section Thickness• Variations in wall thickness can lead to higher scrap rates• Transition design

• Abrupt transitions are stress raisers

Which transition is best?



Finishing Requirements• How clear are your finishing instructions?

• Over processing leads to waste





• Grinding• Does the parting line need to be ground flush?

• Can the foundry design the pattern to eliminate the need for parting line grinding?

• Can raised pads be used for riser and ingate connections?








• Cleaning• Is re-blast after grinding necessary?• Cleanliness of internal passages








• Cleaning• Is re-blast after grinding necessary?• Cleanliness of internal passages

• Packaging • All specific needs should be known before the quoting stage

• Paint, container type, rust protection, packaging methods



Surface Finish Requirements• Must be defined early in the design process




• Think about the application• Is the casting visible or a touch point?




• Think about the application• Is the casting visible or a touch point?• Visually defect free can add 15%+ to the cost





• Process can be engineered to minimize problems






• Use surface finish comparators • C9 Microfinish Comparator






• Use surface finish comparators • C9 Microfinish Comparator• SCRATA plates






• Use surface finish comparators • C9 Microfinish Comparator• SCRATA plates• MSS SP-55



Tolerances• Cast tolerances are influenced by many factors -




• Metal type




• Metal type• Type of molding process




• Metal type• Type of molding process• Size and weight of the casting





• Follow industry standards whenever possible






• Pattern considerations• Materials






• Pattern considerations• Materials• Construction method• Pattern cost vs Dimensional stability



Inspection Requirements• Understand the basic inspections that will be performed




• Typically a Brinell audit




• Typically a Brinell audit• Magnetic particle





• Additional inspection





• Additional inspection• Material certifications• Hardness testing• Ultrasonic inspection• Radiography• Pressure testing



Keys to Success



Keys to Success

Goal is to eliminate or minimize cost drivers before the design is finalized



Keys to Success


Early Foundry Involvement• Start at the concept phase if possible



Keys to Success



Collaboration• Make sure your needs and expectations are known



Keys to Success



Collaboration• Make sure your needs and expectations are known

Design Reviews• Everyone touching the part should be involved



Questions?


dave charbauski caterpillar inc. (retired) · • finish stock • amount can vary with material...

Documents