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1. Use simple shapes, avoid projections

Keep shapes as simple and clean as possible.  Avoid projections except when necessary.

2. Be careful of section thinkness, think about ribs

Sections should be thin, but sufficiently thick to allow proper filling of section.  Ribs can aid in providing strength with minimum increase in weight.

3. Uniformity is the way to go

Uniformity in sections is desirable.  If varied, transition should be gradual to avoid concentration of stress.

4. Go for a slight crown

A slight crown is better than large flat surfaces.  This is especially true where surface blemishes on finished parts cannot be tolerated.

5. Stay away from undercuts

Avoid undercuts that increase die or operating costs.

6. Avoid loose pieces

Unless loose pieces in the tool gain a net saving or are unavoidable (because of the nature of the design), they should not be used.

7. Provide fillets

Provide fillets at inside corners.  Avoid sharp outside corners except at parting lines when dictated by design.

8. Use draft to avoid distortion risk

Draft on cores and sidewalls aids removal of the casting from the die with minimum possibility of distortion.

9. Think about cored holes or recesses

If savings in metal and a reduction of overall cost will result, cored holes or recesses should be specified if they do not greatly increase die cost.

10. Design cored areas carefully

Cored areas should be designed for easy withdrawal of the core and to avoid complicated die construction and operation.

11. Be careful of cored openings

Cored openings should not be excessively deep and narrow because long, thin cores are easily bent or broken.  Core replacement can add substantially to cost.

12. Avoid very small holes or holes in thin walls

Coring of very small holes or of holes in walls that are less than 1/8-in. thick should be avoided unless doing so is less costly than drilling or piercing.

13. Design for minumum core costs within requirements

Recesses and cored holes should be designed for the minimum core costs that will still satisfy other requirements.

14. Consider the size and location of ejector pins

Locate ejector pins where pin marks will not mar the appearance and pin pressure will not affect function of the casting.  Cooling metal tends to shrink with considerable force against parts of the die.  Binding force of this shrinkage must be considered when determining the size and location of ejector pins.

15. Make areas to be polished/buffed accessible

When polishing or buffing will be necessary as finishing operations, all areas to receive such treatment should be easily accessible.

16. Go for minimum flash removal

Design for minimum flash removal to minimize cost.  Hold to the least machining possible.  Locate flash in a plane where it can be removed most easily.

17. Allow enough metal, but not too much

Where machining is necessary, allow enough metal for clean removal but not so much that unnecessarily deep cuts will be required.  Provide means for holding castings in machining fixtures.

18. Threads in casting?

Cast threads in casting when doing so is less expensive than subsequent machining.

19. Lower assembly costs with integral cast fastening

Integrally cast fastening elements should be specified if they will reduce overall costs by lowering assembly costs.

20. Be mindful of tolerances

Do not call for closer-than-necessary tolerances.

21. Design permanent inserts carefully

When necessary, permanent inserts should be designed for easy placement and provided with sufficient anchorage to secure them in the casting.

22. Think about your end product

When castings influence the final appearance of a product, make them visually attractive and in harmony with adjacent parts.

For more information or a design consultation, please call 732-634-3000 or contact us.