Design for Manufacturing, or DFM, is a design approach where manufacturing requirements are incorporated from the outset. Those who only do this afterwards run the risk of costly mould corrections, dimensional deviations, and production delays. In this article, we explain what DFM entails, how a DFM analysis works in practice, and what mistakes it prevents.

What Design for Manufacturing means

DFM is a design approach where manufacturing requirements are considered from the outset. You don't first think about what the product looks like and then how it will be made. You think about both simultaneously.

That sounds logical, but in practice, design and production are still too often separated. An engineer develops the product in CAD, hands over the drawing, and the production partner then discovers that certain geometries cannot be manufactured without additional operations. These extra operations cost time and money that were not budgeted for.

DFM brings that knowledge to the fore in the process. Eurotechniek applies this to every new product that comes in, including with Plastic injection moulding projects in machining operations. We assess the design for manufacturability before a mould is ordered or a machining programme is written.

Why DFM goes beyond a checklist

DFM is sometimes seen as a standard checklist that you work through before production starts. That's too narrow a view. DFM is a way of thinking that runs through the entire design process.

Wall thicknesses in injection moulding. A wall thickness that varies from 1mm to 3.5mm in the same part leads to uneven cooling. This causes shrinkage, warping, and dimensional deviations. A checklist states that wall thicknesses must be consistent. However, a DFM analysis shows which specific adjustment in this design, using this material, resolves the problem.

The difference lies in knowledge of the process. We combine design assessment with process knowledge of injection moulding, milling and 2K applications. This combination delivers advice that is concrete and actionable, not generic rules.

How a DFM analysis works in practice

A DFM analysis at Eurotechniek begins with receiving the CAD model and the technical drawing. We analyse the design on the following points:

• Draft angles and ribs. Are there sufficient draft angles for demoulding? Are the ribs proportionate to the wall thickness to prevent sink marks?
• Gate location and runner system. Where does the gate position come from and how does the material move through the cavity? An incorrect gate location will result in weld lines on visible surfaces or uneven filling.
• Tolerances. Are the specified tolerances achievable for the chosen material and the component dimensions? A tolerance of plus or minus 0.05 mm is realistic for a small metal connector. The same tolerance for a glass fibre-reinforced PA component of 200 mm is not, without additional measures.
• Cooling and cycle time. How can geometry be cooled? Thick sections that cool slowly extend the cycle time and increase the part price.

Following the analysis, we will provide a written report with findings and concrete proposals for adjustments. This report is not a judgment on the design, but a working document to move forward together.

Errors that DFM prevents

The value of DFM lies in what you avoid. A few practical examples demonstrate how small the adjustment can be and the significant consequences without it.

A customer submitted a design for a technical housing in ABS. The walls had no draft angles. The mould was already almost ordered. Following DFM analysis, the drawing was adjusted with 1.5-degree draft angles on all vertical surfaces. Without this adjustment, the mould would have caused ejection problems, resulting in damaged products and extra mould wear.

Another case: a component made of glass fibre-reinforced nylon had shrinkage tolerances specified that were based on unreinforced material. The difference in shrinkage for this material is 0.3 to 0.5 percent depending on the fibre orientation. Without correction, this would have led to dimensional deviations that made assembly impossible. The adjustment cost one hour of work. Correcting the error after production would have taken weeks.

Eurotechniek identifies these kinds of problems for the production phase. That is not an extra service, that is part of how we work.

DFM and die investment

A mould is a substantial investment. Depending on complexity and dimensions, a single injection mould can range from €8,000 to well over €50,000. Subsequent adjustments incur additional costs, both in money and lead time.

DFM protects investment. Those who proceed with a design without a manufacturability check risk corrections to the mould that easily cost between €2,000 and €10,000. These are adjustments to the runner system, cooling channels or cavity geometry that could have been avoided.

We build moulds in-house, with direct access to our tool shop. This means the knowledge from the DFM analysis is immediately incorporated into mould construction. There is no loss of communication between the engineer who reviews the design and the toolmaker who builds the mould. This short line makes DFM effective in practice at Eurotechniek.

DFM for more complex processes

DFM is also relevant outside standard single-shot injection moulding. In the case of 2K injection moulding, where two materials are combined in a single cycle, an additional layer of design requirements applies. The adhesion between the two components depends on material compatibility, surface structure, and the order of injection.

A design that has not been assessed for 2K manufacturability can lead to insufficient adhesion, visible seams, or functional shortcomings. We are observing that customers working with 2K for the first time underestimate the joint geometry. A knurl or mechanical interlock within the design can significantly improve adhesion, regardless of material compatibility.

At Eurotechniek, we carry out DFM analyses for 2K projects as a standard step. We look at the interface geometry, injection sequence, and tolerance build-up between the two components. This provides a better basis for mould design and prevents problems in series production.

Frequently Asked Questions about Design for Manufacturing

Een DFM-analyse moet vroeg in het ontwerpproces worden uitgevoerd.

As early as possible, but also when the design is not yet finished. A DFM analysis at 70 percent of the design yields more than an analysis on a completed design that is already fixed. The sooner the findings are incorporated, the cheaper the adjustments will be. Eurotechniek also assesses early CAD models or sketch designs and provides targeted feedback without the design having to be fully worked out yet.

What is the cost of a DFM analysis and does it outweigh the investment?

The cost of a DFM analysis is low compared to the cost of mould corrections or rework. An analysis typically costs a few hundred euros, depending on the complexity of the part. A mould correction can easily cost ten times as much. Furthermore, a DFM analysis prevents delays in launch, which has considerable indirect value for serious volumes. We always discuss the costs in advance, so you know where you stand.

Is DFM only relevant for injection moulding?

No, DFM is applicable to any manufacturing process. The principles remain the same: design so that the process can be carried out efficiently and reliably. For machining, it's about accessibility for tools and avoiding overly deep, narrow cavities. For sheet metal, it’s about minimum bend radii and punch breaks that don't damage the tool. Eurotechniek works with multiple processes and applies DFM to the process used for your product.

A good design starts with the mould

DFM is not a bureaucratic step in project planning. It's the way a craftsman looks at a design before starting the work. Skipping it will cost more later.

Want to know how your design scores in terms of manufacturability? Get in touch via euro-techniek.nl. We'll take a look together and give an honest assessment, with no obligation.