Design for Manufacturing (DFM)
The best time to solve a molding problem is before the mold is even built.
Design for Manufacturing (DFM) is the process of evaluating a part design against the realities of manufacturing before committing to production tooling. For plastic and thermoset molding, that means looking beyond whether a component works in CAD and determining whether it can be molded reliably, efficiently, repeatedly, and at the intended cost and quality level.
At Davies Molding, DFM brings product design and manufacturing engineering together early in the development process. Our team evaluates the relationship between part geometry, material, molding process, tooling, tolerances, and production requirements to identify potential issues before they become expensive tooling modifications or recurring production problems.
Whether the application requires injection molding, compression molding, or another type of thermoset molding process, early DFM creates a stronger path from concept to production.
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What Is Design for Manufacturing?
A component can meet every functional requirement on a drawing and still be difficult or unnecessarily expensive to manufacture.
DFM identifies that gap.
Before tooling is built, engineers review the proposed design to determine how the selected material will fill the mold, how the component will cool or cure, how it will release from the tool, and whether critical dimensions can be consistently maintained during production.
Common Issues Identified During a DFM Review
The objective isn't simply to make a part easier to mold. It's to balance product performance with manufacturing performance.
Why Early DFM Matters
Once a mold is manufactured, design changes become significantly more complicated.
Moving a gate, changing a parting line, modifying an undercut, adding draft, or changing critical geometry may require tooling modifications, new inserts, welding and remachining, or, in more significant cases, a redesigned mold.
Those changes can mean additional cost and delays before production even begins. DFM moves those conversations upstream.
By elevating manufacturability before steel is cut, engineering teams have more flexibility to make changes when they're still relatively straightforward.
Early DFM can help:
Benefits of Early DFM
The result is a design that considers not only what the component needs to do, but how it will be manufactured thousands or millions of times.
What Davies Evaluates During DFM
DFM involves more than reviewing individual design features. Davies evaluates how part geometry, material selection, tooling requirements, and manufacturing processes interact to support consistent, efficient production.
Wall Thickness
Evaluate wall sections and transitions to improve material flow, cooling or cure behavior, dimensional stability, and cycle time while reducing risks such as sink, voids, and warpage.
Draft Angles
Determine appropriate draft based on part geometry, depth, material, and surface requirements to support reliable mold release and reduce part damage and tool wear.
Undercuts & Mold Actions
Review undercuts and complex features to determine whether slides, lifters, or other mold actions are necessary, or whether design changes could simplify tooling.
Gate & Material Flow
Assess gate placement and material flow for injection molding, or charge placement, venting, and flash management for compression molding, to support consistent part quality.
Ejection & Part Release
Evaluate ejection locations, release surfaces, and part geometry to reduce sticking, distortion, witness marks, and potential component damage.
Parting-Line Placement
Determine how mold orientation and parting-line location affect flash, venting, tool construction, and the appearance and quality of the finished component.
Material Selection Is Part of DFM
A mold can't be designed independently of the material it'll process.
Different materials behave differently under heat, pressure, flow, cooling, and cure. They also have different shrinkage characteristics, reinforcement, abrasion, thermal requirements, and mechanical properties.
Davies works with both thermoplastic and thermoset materials, making material selection an important part of the DFM conversation. Considerations may include:
Material Selection Considerations
A geometry that molds successfully in one material may create challenges in another. Selecting the material early allows manufacturers to develop the part and tooling strategy around its actual processing behavior.
Designing Tolerances for Productions
Tighter is not automatically better.
Every molded component requires tolerances, but unnecessarily tight tolerances can increase tooling complexity, inspection requirements, process sensitivity, and manufacturing cost without improving product performance.
DFM asks an important question: Which dimensions are truly critical to the component's function?
Davies can work with customers to identify critical dimensions and evaluate how material shrinkage, part geometry, tooling, temperature, processing conditions, and secondary operations may affect the ability to hold them.
This is particularly important for dimensions affected by long flow paths, thick sections, warpage, parting lines, secondary machining, etc. The goal is to develop tolerances that reflect both functional requirements and manufacturing capability.
Identifying Molding Risks Before Production
DFM gives engineering teams an opportunity to identify potential molding defects before they appear during sampling. Depending on the material and process, those risks may include:
Sink
Thicker areas, ribs, bosses, and other geometry can create localized shrinkage that becomes visible at the surface.
Warpage
Uneven shrinkage, cooling, cure, wall thickness, or reinforcement orientation can cause the finished component to distort.
Weld Lines
When separate material-flow fronts meet, a visible or mechanically significant weld line may form. Gate placement and geometry can influence where those regions occur.
Flash
Parting lines, shutoffs, vents, and compression-mold geometry must control where excess material can escape.
Short Shots
Long flow paths, restrictive geometry, inadequate venting, or other processing conditions can prevent complete cavity filling.
Identifying these risks in the digital design allows engineers to evaluate solutions before they become physical tooling problems.
DFM for Injection Molding vs. Compression Molding
The principles of DFM remain consistent across molding processes, but the engineering priorities change.
| Design Consideration | Injection Molding | Compression Molding |
|---|---|---|
| Material Delivery | Runner and gate strategy | Charge size and placement |
| Flow | Fill path, pressure, shear, and packing | Charge flow and pressure distribution |
| Temperature | Cooling and thermal balance | Heating and cure uniformity |
| Material Behavior | Melt flow and shrinkage | Flow, crosslinking, and cure |
| Part Release | Ejectors, slides, and lifters | Draft, release, and removal strategy |
| Excess Material | Runner/Gate management | Flash management |
| Venting | Trapped air and process gases | Air and cure-related gases |
| Primary Cycle Concern | Filling, packing, and cooling | Filling, cure, and release |
Understanding these differences is especially important when determining which molding process is appropriate for a new component.
From DFM to Tooling to Production
The greatest value of Design for Manufacturing comes from connecting early design decisions to the entire manufacturing process.
A seemingly minor design change may eliminate a side action, improve gate placement, reduce sink, or simplify part ejection. Revisiting dimensional tolerances may also eliminate unnecessary secondary machining or inspection.
Individually, these decisions may appear small. Across the life of a high-volume production program, however, they can influence:
Manufacturing and Production Benefits
- Tooling investment
- Cycle time
- Scrap reduction
- Maintenance requirements
- Automation opportunities
- Secondary operations
- Part quality and consistency
- Production uptime
- Cost per part
Connecting Design Decisions to Production
Davies evaluates components with the downstream manufacturing process in mind, from material selection and mold design through sampling, validation, production, and ongoing tooling support.
By connecting these stages early, Davies helps customers develop the part, mold, and manufacturing process as one integrated system, reducing manufacturing risk and supporting more efficient production.
Start with DFM Before You Build the Mold
The costliest time to discover a manufacturability problem is after the mold has already been built.
Bring Davies Molding into the process early. Whether you're developing a thermoplastic injection molded component, a compression molded thermoset part, or evaluating the right manufacturing process, our team can help identify molding risks, evaluate material and tooling requirements, and improve manufacturability before production begins.
Contact Davies Today →Have any questions about materials and capabilities?
Contact Us through our online form or call 1-800-554-9208.