Blog sharing 2026-06-17
A mold quotation is only useful when the part requirements behind it are clear. Before pricing and tool design, a DFM review should identify the decisions that affect mold structure, molding risk, part quality and the assumptions included in the quote. The goal is not to redesign the product automatically. It is to make technical questions visible before steel is cut.
For an initial review, provide the latest 3D CAD file and, where available, a 2D drawing. The review becomes more useful when the material grade, annual quantity, target surface, critical dimensions, assembly conditions and expected project timing are also stated. Mark cosmetic surfaces and functional interfaces instead of asking the mold maker to infer them.
STEP, STP, IGS, X_T and native CAD files are generally more useful for geometry review than an STL alone. A drawing remains important when it defines tolerances, inspection datums, texture, color or notes that are not stored in the 3D model.
Check whether nominal walls are reasonably consistent and whether thick-to-thin transitions are gradual. Local thick sections can cool more slowly and increase the risk of sink marks, voids, differential shrinkage or a longer cycle. A thin restriction may create filling pressure or short-shot risk. The correct wall range depends on the resin, flow length, geometry and performance requirement, so a single universal number should not be applied to every part.
Faces parallel to the mold-opening direction need suitable draft. The required angle depends on depth, resin, texture, polish and the direction in which the part stays during opening. Texture normally needs more draft than a polished surface. The DFM should clearly show the proposed opening direction and identify faces where insufficient draft could cause drag marks, deformation or difficult ejection.
Ribs and screw bosses should support function without creating unnecessarily thick intersections. Review their thickness, height, root transition, spacing and connection to the main wall. Bosses may need gussets or a controlled gap from nearby walls. The appropriate proportions depend on material and load; they should be evaluated together with visible-surface requirements rather than copied from a generic rule.
Identify every feature that prevents straight pull. Decide whether each undercut can be removed, redesigned for a shutoff, or requires a slider, lifter or other mechanism. Then review the parting line, shutoff conditions and likely witness marks. Ejector locations must support the part without damaging cosmetic or sealing surfaces. These decisions can materially change tooling cost and maintenance, so they belong in the quotation discussion.
A preliminary gate concept should consider flow length, filling balance, gate vestige, weld-line location, air traps and how the part will be trimmed or handled. For multi-cavity tools, balance and repeatability also matter. A DFM can identify likely concerns, while detailed gate sizing and process settings are refined during tool design and, where appropriate, supported by technical analysis.
Name the intended resin and grade when possible, including reinforcement, flame rating, color or recycled-content requirements. Shrinkage is affected by material, fiber orientation, geometry, gate position and processing conditions. Tolerances should distinguish critical-to-function dimensions from general dimensions. Very tight tolerances across every feature can increase tool adjustment and inspection effort without improving product function.
The expected annual quantity, total program volume and launch schedule help determine the appropriate tool concept, cavity count, steel selection, hot- or cold-runner approach, spare strategy and validation plan. These inputs should be stated before comparing quotations. Two prices based on different production assumptions are not directly comparable.
An early DFM review is a decision tool, not a substitute for final mold design, detailed simulation, tool trial or process validation. Its value is to expose obvious risks and missing inputs early enough for the product team and mold maker to agree on the quotation basis.
Tec-Shine provides a free first-step DFM review within 48 hours for new plastic part projects. You can submit CAD files and project requirements through the secure DFM review form. For confidential projects, review the CAD confidentiality and NDA process before sending detailed data. Mold construction scope can then be aligned through our injection mold manufacturing service.
Share CAD files, material, volume and timing. Tec-Shine will review manufacturability and quotation direction.
