Consider the path of the cutting tool
Think of a junction block with a deep machined pocket and narrow corners inside. Although the screw female measures may seem simple, a small inner radius may require a thinner cutter. When the depth increases, the access and rigidity of the cutting tool are also brought up. The detail drawn in a few seconds on the CAD screen may be the cause of a separate operation in production.
Therefore, the first question in the design review should not be limited to "Can we do this?" The question should also be asked, "Can we provide the same function with a geometry that is more easily processed?" If the change affects the strength of the part or its relationship with the co-part, the design supervisor needs approval.
Not every surface has the same significance
A bearing diameter and a purely cosmetic surface serve different purposes. Applying the same tight tolerance to both can increase inspection and machining time without improving function. Clearly identifying the critical surface directs the manufacturer’s attention to the right feature.
Similarly, describe the relevant surface rather than just spreading the required roughness value across the entire part in the sealing area. Detailed examples the tolerance selection guide You can.
Compare the two versions when asking for an offer
For example, if the interior corner of a enclosure does not affect the assembly, prepare a wider radial alternative next to the current model. Ask the manufacturer to explain not only the new price but also what preparation or operation has been eliminated so you can see the design change's return.
Send the alternatives with separate revisions. Two different models of the same name create a new uncertainty when looking for savings. Also state in writing that the unapproved alternative should not be put into production.
Four questions to be taken to the purchase interview
- Is this detail necessary for the piece to work?
- Can it be harmonized with a standard cutting tool or stock measure?
- Do you need separate workholding or special control for this surface?
- Does the change affect only the unit price or the preparation time?
One prepared with these questions bid fileStarts a more efficient meeting than requesting "let's lower the price". Get your current drawing and the areas that can be changed to FactorAB you can communicate together.
Sources and further reading
- Protolabs Network Design decisions that reduce cost in CNC parts
- Protolabs Network Design guide for CNC
- Thomasnet CNC machining process and operations
This article is an original narrative that deals with technical principles in resources through the process of parts and bids. Examples are for disclosure purposes; it does not mean partnership with resource organizations or their approval of FactorAB.