Injection Molding
Tooling and molding for your repeat plastic parts.
YOUR FEATURES. YOUR MATERIAL. YOUR MANUFACTURING REVIEW.
Part Design Guidelines Make Your Next Drawing Easier to Review
Connect tool access, molded features and locating interfaces to the function of your part. Use this guide to prepare better questions before your design, process and inspection scope are agreed.
Internal Corner Radius for Your CNC Design
Use these CNC part design guidelines to review internal corners, pocket depth and tool access together. A small corner can constrain the available cutter even when the rest of the pocket is open.
Corner radius and idealized tool diameter
For a perpendicular cylindrical cutter in an idealized pocket: tool diameter ≤ 2 × internal corner radius. Zero baseline 0–8 mm.
These are geometric examples, not recommended cutters or process limits. Actual machining needs clearance, reach, material and vibration review; a smaller tool may be required.
The photograph illustrates rounded corners and has no assigned dimensions. Background reference: Protolabs on tool access and internal radii →. Tool geometry does not establish LK MFG capability or a quoted cycle time.
Choose the Design Questions for Your Process
Machined pockets & faces
Review tool access, corner relief, reachable holes and the surfaces that control final fit. Review CNC manufacturing →
Molded walls & bosses
Review draft, wall transitions, ribs, resin and the expected appearance before tooling. Review molding →
Formed panels & brackets
Review bend access, hole-to-bend relationships, hardware and the assembled envelope. Review sheet metal →
A Plastic Design Guide for Your Molded Part
For injection mold design and build, review the finished part, tooling approach and resin together. A change to ribs, bosses or appearance may also change the mold and approval plan.
Walls & ribs
Review wall transitions, rib intersections and material accumulation against your resin and function. There is no universal wall thickness for every polymer.
Bosses & hardware
Injection molding boss design guidelines depend on resin, mating hardware and tooling. Define the fastener, engagement and surrounding structure.
Draft & appearance
Identify release direction, texture, parting lines and visible surfaces. Agree cosmetic acceptance separately from dimensional requirements.
Reference topics: Xometry injection molding guide →. Supplier-specific limits are not adopted as LK MFG promises.
Separate Your Locating Features from the Clamping Plan
For tool and fixture design, identify the contact datums, supported surfaces and clamp access. A manufacturing fixture review does not replace your equipment design or application validation.
Locate the part
Show the features that establish position and orientation.
Support the load
Identify supported faces and features that must not distort or be marked.
Reach the features
Consider cutting, assembly and inspection access in the intended setup.
6 Inputs for Your Design Review
- CAD and controlled drawing revision.
- Part function, mating components and assembled condition.
- Material grade, condition and product form.
- Critical features, surface finish and appearance zones.
- Sample quantity, revision plan and repeat demand.
- Inspection methods, required records and approval owner.
Answers Before You Release the Drawing
Does every feature need a tight tolerance?
Identify the dimensions that control function and assembly. Agree the remaining requirements rather than tightening the complete drawing without a reason.
Can a 3D CAD model replace the drawing?
Use the model for geometry and define controlled units, tolerances, material, finish and acceptance requirements in the agreed drawing or specification.
What changes for two-shot molding?
A two-shot molding design guide must address resin compatibility, interface geometry, mold architecture and equipment requirements. Review availability and project scope before assuming this production route.
Can these geometric examples be used as a supplier capability claim?
No. They explain a geometric relationship. Actual tool choice, setup, process limits and acceptance must be confirmed for your drawing.
Continue with the Decision Your Part Needs
Drawing review
Connect tolerances, datums and inspection. Review tolerance and GD&T →
Material & process
Compare the grade, geometry and manufacturing route. Review material and process selection →
Quote preparation
Send a controlled baseline for a useful quote. Use the RFQ checklist →
