DFM guide
10 ways to reduce the cost of a metal part before producing it
Most of a part’s cost is decided on the drawing, not in the shop. Here are the ten points our engineer checks at every DFM review.
The ten points
- 01
Use standard profiles
A 2 × 2 × 1/8 HSS is stocked by every distributor. A rare size is paid in lead time and purchase minimums.
- 02
Make notches and holes at the cut
Anything drilled or ground after the cut is one more operation. On a tube laser, it is included in the same pass.
- 03
Replace jigs with coped joints
A notched crossmember that slots into its upright positions itself. The jig disappears, and so does the squaring.
- 04
Reduce the number of welds
Two welded parts can often become one bent part. Every weld avoided removes time and distortion.
- 05
Tighten only the useful tolerances
A ± 0.1 mm tolerance on a dimension that mates with nothing costs one more check. Identify the critical dimensions, leave the rest standard.
- 06
Keep welds off visible surfaces
A hidden joint is MIG-welded, fast. A visible joint is TIG-welded and finished. The drawing decides which.
- 07
Plan the finish from the drawing
Powder coating needs hanging points and drain holes. Galvanizing needs vents. Planned on the drawing, they cost nothing.
- 08
Pick the material for the use, not by habit
Stainless costs three to four times steel. With no food contact and no corrosion, galvanized or painted steel is often enough.
- 09
Group the quantities
Programming and setup happen once per lot. One hundred parts in one lot cost less than four lots of twenty-five.
- 10
Send a clean 3D file
A STEP with the right thicknesses avoids remodelling. A sketch works too, but adds drafting time.
What a DFM review is worth
On the parts we receive, the DFM review often finds 10 to 20% of cost to remove without changing the function. Sometimes more, when a frame moves from saw to laser.
The review is included in the quote. You receive the proposed changes in writing and decide which to apply.
A well-designed part costs less at every supplier, not only at ours. That is the reason for publishing this list.