The fourteen DFM checks, and what each one catches
A DFM report is only useful if it is specific. These are the fourteen items TJ-Teck reviews on every 3D model, and the failure each one is there to catch.
8 min read · TJ-Teck engineering notes
Direction, layout and the parting line
De-molding Direction, Mold Layout and Parting Line are decided together and they constrain everything after them. Get the pull direction wrong and features that could have been straight-pull now need slides, which adds cost to every tool built from that design.
Slides, lifters and their steel lines
Slide Design & Steel Line and Lifter Design & Steel Line are separate items because the steel line is where a slide fails. Too little steel behind a slide face and it deflects, which shows as flash that gets worse across the run.
Draft and wall thickness
Draft Angle Analysis and Wall thickness are the two items that most often need a part change. Too little draft on a textured face means drag marks. A rib thicker than about two thirds of its wall means a sink mark on the opposite face.
Inserts, sharp steel and undercuts
Inserts Design, Sharp Steel and Undercut and Proposal cover the places where the tool is fragile. Sharp steel is any thin, unsupported steel condition created by the part geometry, and it is the thing that chips in week three of production.
Filling, gating and ejection
Filling System, Gate Define and Ejection System decide how the part is made and how it comes out. A gate in the wrong place puts a weld line on a visible face; an ejection pattern in the wrong place bows a slim part on the way out.
Markings and graining
Markings and Graining covers date stamps, cavity numbers, recycling marks and the surface texture. It is last on the list and it is the item most often left until the tool is finished, which is exactly when changing it is most expensive.
The fourteen items in order
- De-molding Direction
- Inserts Design
- Parting Line
- Slide Design & Steel Line
- Draft Angle Analysis
- Lifter Design & Steel Line
- Mold Layout
- Sharp Steel
- Filling System
- Wall thickness
- Gate Define
- Ejection System
- Undercut and Proposal
- Markings and Graining
Frequently asked questions
Do you send the report before or after the order?
The DFM report is issued before mould construction begins, and construction starts after the points in it have been agreed with you.
What if a finding conflicts with our industrial design?
The finding is recorded, the alternative is explained, and the part is built as you decide. The report exists to make the trade-off visible, not to overrule it.
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6 min readApply this to your own part
Send 2D and 3D data with the annual volume and the surface requirement. A quotation comes back in 1-3 working days.