Measurement by mouse click in the machining centre

By Niraj M Wanikar, Chief Editor, CNCTimes.com, 2016-07-19 13:03:00

Quality is the top priority in the automotive industry. Model and Mold maker Sammer, located in Eugendorf near Salzburg, Austria, places its trust in FormControl when it comes to meeting the high accuracy demands imposed. Blum-Novotest measuring software enables quick and easy workpiece checking in machining centres.

Sammer's customer base includes leading corporate names such as BMW, AVL and Nemak. It is mostly engaged in the production of molds for the automotive industry, including cylinder heads, crankcases and transmission housings. Models are mostly milled from a special plastic known in the industry as Ureol. It is a PU resin soaked with filler. It offers outstanding machining properties, and is used primarily in model and mold making. In the next step, the milled molds are then encased in a molding box filled with molding sand and compressed by stamping, pressing or machine vibration. When the model is removed, a negative mold is left in the sand into which the molten metal is then poured to make the prototype.

Blum-Novotest's FormControl measuring software is installed on seven 3- and 5-axis machining centres in Eugendorf. The software is used to measure every milled item in the machining centre. It measures contours, bores, angles or distances. "A big benefit of the software is that we are able to measure our workpieces in their original clamp fixtures in the machining centre. That saves us a lot of time, because we can do any necessary reworking immediately," explains production manager Johann Pucher, who has been working for Sammer for 40 years. "So the time-consuming process of unclamping, transporting to the measuring machine, measuring, reclamping, aligning and reworking is now a thing of the past."

The range of highly complex molds which Sammer makes for its customers is widespread and tight tolerances of five hundredths are the norm. The FormControl measuring software provides the ideal complete package to meet them. That is because each production operative designs, machines and measures each component himself, so it is important to have a software programme that is quick and easy to use: First the CAD data is imported into the programme. In the programme, the measuring points can be optimised and new ones added or existing ones moved by a simple mouse-click on the PC.
Automatic PC-based collision control prevents unintentional collisions between the workpiece and probe. The NC programme is transferred to the controller and the measuring sequence can be started. After the measurement, the results are sent back to the PC, then the individual measuring points can be colour-coded, enabling tolerance evaluations to be made easily. At the end, a measuring report presenting the individual measuring points in tabular form can be exported.

Before the Blum-Novotest software was installed, Sammer had relied blindly on the quality of the milled molds. This was sometimes problematic, because setting errors, tool wear or machine temperature drift could quickly cause the tight tolerances to be exceeded. Today, by contrast, the Austrian company is fully assured and able to verify the quality of the workpieces it mills. Previously, if an error occurred in the customer's casting process, the mold was sent back to Sammer for reworking.

Now the model and mold maker has the measuring report documenting the quality of the milled molds. As Managing Director Günter Sammer stresses: "The reports are now an essential tool for us, not least because some customers actually stipulate them. And a report is produced and saved for each workpiece we mill, enabling us to react to any refer-backs. It is especially beneficial as it entails no additional work for the production staff. Quite the opposite: the reports are generated almost entirely autonomously, and can be immediately edited as necessary."

The outstanding material properties of the plastics for the milling process enable ultra-fast cutting speeds. Nevertheless, some molds spend as much as 50 hours in the machining centre being milled. Such components are of course very expensive – due to the long machine running times alone – so it is essential to avoid any machining errors. Large components can easily have more than 100 measuring points on them.

When working to very tight tolerances, Sammer sets several points manually, as a precaution. Other molds are made of steel. Tool wear is a bigger concern in those cases than when machining plastics. For steel components, the workpiece is measured during machining, so as to guarantee perfect quality. Lots of different plastic molds are made, however – sometimes 5 to 8 per day. The costs vary widely, because the specialists at Sammer not only collate milling data and mill the components, but often also prepare the CAD data and design components prior to milling, and sometimes also fabricate and assemble slit dies and ejector or closure systems. In view of such complex processing and the associated high cost, it is essential to install safeguards and monitor quality.

FormControl has absolutely proved its worth in Eugendorf. Sammer first made contact with Blum at a trade fair, and has been using the software since 2010. The user-friendliness of FormControl is what the model and mold maker particularly appreciates. "I had learnt the software after just half a day's training, and was then able to pass on my knowledge to my colleagues without problem," Johann Pucher sums up his positive experience. "We are also delighted with the service backup in general, and especially with the level of cooperation from Blum. They are always open to our ideas for new features or improvements to the software.”

http://www.blum-novotest.de/company/news/news-ansicht-template/article/perfect-molds-for-the-automotive-industry.html

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