DFM rules
What each design-for-manufacture check looks for in every process Quotometry prices, how to set its threshold and action, and what your buyer sees when it fires.
This article explains Quotometry’s design-for-manufacture (DFM) checks: what each one looks for, what it can do when it fires, and how to set it for your shop. A DFM check catches a part that cannot be made well at quoting time, while it is still free to fix. Every check measures the geometry against the limits of the process the buyer chose, so “thin” means a number, not an impression.
What each process checks
Every process checks that the part fits a machine you have, in some orientation. A part that does not fit gets a clear “too big for us” rather than a price you cannot honour.
| Process | Checks |
|---|---|
| FDM | Thin walls · gaps too narrow to stay open · bed-adhesion risk from a small footprint · warp risk on long, flat parts · overhangs that need support · bodies that run through one another · meshes that cannot be repaired |
| Resin (SLA, DLP, LCD) | Thin walls · gaps too narrow to stay open · peel force on large cross-sections · resin trapped in a sealed cavity · tall, thin parts that will fail · unsupported islands · detail finer than the machine can resolve · bodies that run through one another · meshes that cannot be repaired |
| SLS and MJF | Thin walls · gaps too narrow to stay open · powder trapped in a cavity with no escape hole · warp risk · thick sections that will sink · parts too small to find in the build · bodies that run through one another · meshes that cannot be repaired |
| Metal (DMLS, SLM, LPBF) | Thin walls · gaps narrow enough for powder to sinter across · powder trapped in a cavity · detail finer than the powder allows · tall, thin parts · cross-sections large enough to build up residual stress · heavy support · bodies that run through one another · meshes that cannot be repaired |
| PolyJet and material jetting | Thin walls · thin rubber-like walls · detail finer than the material allows · bodies that run through one another · meshes that cannot be repaired |
| Binder jetting | Thin walls · detail too fragile to survive as a green part · gaps too narrow to stay open · powder trapped in a cavity · metal parts likely to need setters in the furnace · bodies that run through one another · meshes that cannot be repaired |
| CNC milling | Internal radii smaller than your smallest end mill · pockets deeper than the tool can reach · deep holes · holes smaller than your smallest standard drill · undercuts the machine cannot reach · large thin plates · thin walls · a mesh upload whose holes and pockets are unknown · a tolerance or finish you review · bodies that run through one another · meshes that cannot be repaired |
| CNC turning | Parts that are not mostly round (mill them instead) · long, slender parts · thin tubes · deep bores · diameters smaller than the lathe handles · off-axis features that need a second operation · thin walls · a mesh upload whose features are unknown · a tolerance or finish you review · bodies that run through one another · meshes that cannot be repaired |
| Laser, waterjet and plasma | Contours that do not close · text not converted to outlines · holes smaller than the thickness allows · webs too narrow to cut · duplicate lines · tiny entities · pieces small enough to fall through the slats · engraving on a machine that cannot engrave |
| Injection moulding | Thin walls · thick walls · a large spread between the thinnest and the typical wall · side actions the tool needs · a trapped volume · bodies that run through one another · meshes that cannot be repaired |
| Vacuum casting | Thin walls · thick sections · undercuts that add mould pieces · a trapped volume · bodies that run through one another · meshes that cannot be repaired |
What a check can do
You choose, per check:
| Action | What happens | Right for |
|---|---|---|
| Warn | The buyer is told, can acknowledge it, and can still order. | Risks that depend on how the part will be used. |
| Block | No price, and a clear explanation of what is wrong. | Things that will certainly fail: trapped resin, a wall far below what the process can make. |
| Review | The quote goes to your Inbox instead, with the part already measured. | Cases where it depends, and you would rather look yourself. |
Set the thresholds
Start with the defaults: they are the honest limits of each process. Tighten a threshold when a part failed that the check let through. Loosen one when you keep overriding it: a check you override every time is training you to ignore checks.
Thresholds are set per process. A 0.8 mm wall is comfortable in FDM, marginal in SLS and fine in resin, which is why the numbers are not shared.
What the buyer sees
The finding in plain language, where it is on the part, and what would fix it, never a bare code. The wall-thickness heat map in the viewer shows exactly where the part is too thin, using the same measurement as the check.
A buyer who is told their 0.4 mm web will not survive depowdering has been given useful engineering advice, and remembers it. A buyer who finds out from a broken part has been given a refund and a reason to look elsewhere.
File repair
Most uploaded files are not watertight. Duplicate vertices, flipped normals, small holes and self-intersections are repaired where the repair is unambiguous, and the part is measured from the repaired mesh so the price is right. What cannot be repaired is reported rather than guessed at.
Codes
Every finding has a stable code, because it is stored in quotes and sent in your webhooks. The full list is in the developer documentation.
Next steps
- Manual review: route a finding to a person instead of blocking it.
- Troubleshooting: files that will not analyse.
- Errors: DFM codes as your integration sees them.