In most parts produced by pressing, a protruding burr is created during mould separation. Examples of this include fitting parts, housings, aluminium rims or motorbike rims made of carbon – the specific example used in the following case study. Selection of the optimum deburring process is determined by factors including the following: the thickness of the burr, the workpiece contour and the required deburring quality. But one question is pivotal: How can we automate the finishing of such parts?

Various challenges

This task is made up of several unknown components that solutions must be found for:

1. No impairment of the rim shape: Above all, it is essential that the basic structure of the rim remain unmachined.
2. Inaccurate positioning: Precise positioning is not possible due to the production process and the rim shape, which consists of different radii.
3. Irregular thickness of the material protrusions: As a result of dependence on the flow behaviour, the thickness and position of the protruding material cannot be clearly defined in advance.

1st partial solution: Automatic compensation of position differences

To solve this rather complex task, it must be broken down: The first step is to find a solution through which to compensate for the respective dimensional and positional differences. Tools with laterally deflecting spindles are available on the market for this purpose, whereby these are usually primarily used for the automated deburring of parts with undefined edges.

2nd partial solution: Special milling cutter with integrated stop system

As previously described, during rework it is necessary to ensure that only the protruding material residues are removed. This means that the basic structure of the rim must remain fully intact and unaffected.
To ensure this is the case, special cutters with an integrated stop are used for reworking. Depending on the application and the available space, these consist of a guide roller or a ball bearing that rolls on the material edge. Used in combination with the deflecting tool spindle, this tool unit even automatically compensates for deviations from the workpiece contour for programming.
The upshot: Transition-free milling off of material residues and burrs, together with assurance that the part contour will not be milled into.

Costs are reduced, while quality is also improved

In production, the changeover to this tooling solution has had a positive effect in several respects: Whereas it was necessary in the past to pre-mill parts with additions first and then carefully rework them by hand, today the entire process is fully automated. The time and cost savings associated with this are also accompanied by an increase in process reliability.
Do you have any questions on the topic of “Milling off of protruding burrs on pressed parts“? Contact us.

Most weldable steel types are not optimally suited for machining due to the alloy components. This means that when welded parts are milled over, a strong and tough burr is often produced.

Great effort with manual deburring

While burrs from free-cutting steel or cast materials can easily be removed with hand deburring machines, welded parts require more effort: In addition to larger machines, this also requires considerably more time. Thus, manual deburring of welded parts only makes sense for small quantities. For larger series, an automated solution is therefore required.

Challenges in automated deburring

Depending on the size and complexity, the dimensional tolerances on welded parts are usually several millimetres. In addition, there are often additional position differences during workpiece clamping for reworking. For reasons of efficiency, part machining and deburring should be carried out on one machine with the same clamping. Due to the dimensional or positional differences of the edges to be deburred, an appropriate solution is required. The good news: For several years now, deburring tools with deflectable spindles have been available for this purpose, which automatically compensate for the differences between the programmed and effective workpiece contour.

Process reliability is crucial

However, a prerequisite for an automated process is an absolutely reliable procedure. When deburring welded parts, increased demands are placed on the deburring tool. Depending on the machining direction, burrs of different thicknesses often appear on the same part. However, with appropriate tooling solutions and matching cutters, it is still possible to provide all edges with uniform deburring. When purchasing the deburring tool, it is therefore worthwhile to trust a competent supplier with the necessary experience in corresponding applications.

Do you have any questions on the subject of “Automated solutions for machining burrs on over-milled welded parts”? Contact us.

Although they often receive little attention, pneumatic tools are used in practically all production plants. High-speed air-driven spindles in particular are among the real energy guzzlers, as the generation of compressed air requires a lot of electrical energy. In this article we take a closer look at this highly topical issue.

Deflectable, electrically driven deburring spindle

In mid-2021, for example, the 24-hour operation of a compressed air spindle with 300 W power and a speed of 35,000 rpm caused daily energy costs of 10-20 euros. Extrapolation to the current electricity price is up to you.

Take a mental – or physical – walk through your company and see where compressed air spindles are used. And/or have your responsible employees evaluate the energy consumption of your compressed air preparation systems.

Alternative: Electrically operated high-frequency spindle

Electrically operated high-frequency spindles are an extremely sensible alternative, especially for automatically operated systems with built-in spindles. In addition to the incomparably lower energy consumption, these spindles offer further significant advantages over the compressed air-driven versions: load-independent speed stability, possibility of preselecting different speeds, a wide range of monitoring functions, etc. In addition, the electric spindles are completely maintenance-free, whereas with lamina-driven compressed air spindles, wearing parts have to be replaced after a few thousand hours of use.

Conclusion: Conversion is also often worthwhile

Today, it goes without saying that energy consumption is taken into account in new installations. However, this should not only be considered when buying new. It is advisable to also check existing installations from this point of view. Due to the potential savings in energy and maintenance, the costs of a conversion from compressed air to electric spindle can often be amortised in a surprisingly short time.

Do you already use marking systems or do you have your parts marked externally?
In this article, you can get some interesting input about the different procedures, as well as their advantages and disadvantages.

The most widespread processes

When it comes to the topic of part marking, the key term “laser marking” pops up in many of our minds. This is justified, as lasers can be used to mark a wide variety of materials and surfaces extremely quickly and easily. In addition, most systems are quite easy to programme.

So is laser marking the undisputed solution? Not quite. Even though prices have dropped considerably in recent years, a five-figure investment is still required for a high-performance laser system. For some time now, scribing or needle embossing machines have established themselves as a much more cost-effective alternative. Apart from the price, these systems also have the advantage that no protective devices are required for their operation. For the marking of individual workpieces or small series of up to a few hundred pieces, corresponding machines are also used successfully in many companies.

Compromises in efficiency and process reliability

Whether laser or needle marking machines – with both systems, part marking takes place in a separate work step. Each part is placed or clamped in the marking station after processing. This means: additional, manual parts handling, sometimes combined with additional repacking or transport.

And it is not only those responsible for QA who know that every manual activity reduces process reliability, as every employee, no matter how reliably they work, can make a mistake.

Alternative: In-Prozess-Beschriftung

True to the motto: Complete production on the machine, these disadvantages can be completely eliminated.

In the table below you can see a list of the different methods, as well as the associated advantages and disadvantages. This overview table will help you choose the most suitable marking method.

Would you like to get a deeper insight into the topic? Here you will find more detailed information on the topic of processes and methods for part marking.