Why technical drawings decide cost and quality of custom parts

Technical drawings: a language that works worldwide

When people think of technical drawings, they picture dimensions, lines, and standards. Christian Meistrell, Deputy Technical Lead at Daniel Gruppe, goes one step further.

„Technical drawings are basically a language of their own – someone in China can work with them just as well as someone in Germany, France, or the US.“

– Christian Meistrell,
Deputy Technical Lead at Daniel Gruppe

If some of these technical terms are missing, misunderstandings are inevitable. With customised special components, this is exceptionally critical, because any room for interpretation can quickly turn into component defects or production-line stoppages.

Completeness is the key to a technical drawing

Many people ask what makes a good drawing. But focusing only on “good vs. bad” is too simplistic. The decisive question is: does the drawing contain all information needed for the most cost-effective production?

There is no standard checklist for completeness. Every part has different requirements. The range spans all manufacturing routes – from stamped and punched parts to highly complex machined components. Still, two key steps are always the starting point:

1. Understanding the requirements: What does the custom part have to do? Where will it be used?
2. Defining the production method: How can the part be manufactured as cost-effectively as possible?

If you follow this sequence, you avoid the most common issues from the start. Our engineers support you in Engineering & Design Support and ask the key questions at the right time – down to the smallest detail.

Real-world case study: Thinking outside the box

When developed it was something special; today it is ubiquitous: when you close a drawer at home, you expect it to slow down gently and come to a quiet stop. In the drawer-damping system of a world-leading manufacturer of furniture fittings, a plastic part had to be permanently joined to a metal part. The company approached Daniel Gruppe to find a solution that was both high-quality and cost-effective.

If components need to be permanently joined, welding is often the preferred method. For this, the plastic part must be equipped with a weld stud: the stud is pressed into the plastic – creating a range of technical challenges. Based on this, Daniel Gruppe’s engineers created an initial design. 

• They needed a dimension that still allowed the studs to be pressed in easily,
• but also held firmly so they would not loosen or fall out due to vibration or shock.
• So the diameter and length of the press-fit area had to be aligned precisely and implemented in production.
• This ensured reliable use at eight-digit annual volumes.

For initial sampling, turned parts were produced as prototypes. Many work steps were handled by Daniel Gruppe, including:

• Initial design layout
• Detailed manufacturing plans
• Highly reliable final inspection via automated optical sorting

The challenge:

After machining, the goal was to achieve optimal unit cost by switching serial production to cold forming. Cold forming significantly reduces production time per part and therefore improves cost efficiency. Unlike machining, it also avoids material loss from chips. However, it requires a precisely calculated combination of the optimal blank (wire segment for pressing) and accurately manufactured pressing tools at every stage.

Serial production with special requirements

After the machined prototypes were tested by the customer and checked in the lab, it was clear that the design met the requirements– and implementation as cold-formed parts could begin. Together with a carefully selected manufacturer, and thanks to detailed planning, the project was successfully scaled from a pre-series into mass production.

This is where a holistic project approach proves its value: commercial and quality aspects merge – from the first drafts to final inspection – into an ideal product.

Within just 18 months, Daniel Gruppe supported the project from the first idea to serial production. To date, almost half a billion studs have been produced. The foundation was a long-standing, trust-based collaboration between Daniel, the customer, and the final manufacturer.

Tolerances: as precise as needed – not as precise as possible

Every technical drawing defines tolerance ranges. The key question for engineers is: which tolerance is sufficient for the application? Even in the automotive industry, not every part needs maximum precision.

Conclusion: what really matters for custom parts

The completeness of all relevant information determines how cost-effective your technical drawing is – because gaps lead to higher costs. If you define the production method only after the drawing is finished, you risk uneconomical solutions. We identify optimisation potential and advise you as a partner. Your advantage: Daniel Gruppe offers a network of technical drafters, experienced engineers, and global production sites. With us, you get technical drawings and application-ready custom parts from a single, accountable source. This saves cost, effort, and time.

„Many parts can be realised technically. They only become economical, however, when the technical drawing considers the production method from the very beginning.“

– Christian Meistrell, Deputy Technical Lead at Daniel Gruppe

Knowledge that connects

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