Per trovare il Suo referente

Per trovare il Suo referente

Trovare l'argomento
Cambia lingua

16-Dec 2021: Reduce setup times

Shrink fit technology and tool presetting ensure short setup times and productive machining for Swiss-type automatic lathes.

Dental Direkt, a full-service provider of dental laboratory equipment, has added a shrinking and presetting machine from HAIMER for manufacturing their dental prosthetic parts. Setup for Swiss-type automatic lathes is now many times faster, leaving the machines free for more valuable machining time.

When it comes to dental prostheses, advanced dental implant technology is now the first choice. Around 1.3 million implants are carried out annually in Germany alone – and the trend is increasing (Source DGI, 2018). Dental Direkt from Spenge in North Rhine-Westphalia (also see the info box) is a provider of dental implantology. Jakob Röttger, head of technical sales describes his company: “Dental Direkt is one of the largest manufacturers of dental zirconium oxide in Europe. We are also a full-service provider with products covering the entire workflow of dental technology.”

Implant prosthetics – a growing business area

The DD Solid Connect implant prosthetic system is one of the latest products to join the Dental Direkt portfolio. It contains components such as Prefab, Scanbody, Laboranalog, individual abutments, titanium base bonds as well as laboratory and implant screws. The parts are produced in the 1,500-square-meter manufacturing and technology center in Melle, which was opened in 2015.

“Our system for implant prosthetics is becoming increasingly popular,” Röttger is pleased to report. Dental Direkt is continuously expanding its fleet of machinery to meet the ever-growing demand. Machines include precision turning and milling machines as well as eight Tornos Swiss-type automatic lathes from the Swiss GT 13, GT 26 SwissNano product series with bar feeders. The Tornos machines primarily produce high-precision laboratory and implant screws, titanium base bonds and individual abutments. “These are very complex parts in terms of the quality and precision required,” explains Röttger. “We need an optimized production process to be able to manufacture them economically here on a German site.”

Long setup times put the brakes on productivity

What was not so important with smaller quantities initially became significant with the growing demand for turned parts and their number of variants. The setup times for Swiss-type automatic lathes were too long for economical production. “We now handle 37 different implant connections, which reduces our batch sizes to only around 600 to 1,000 parts, “ Röttger states. “On average, this means that we have to retool the machines every second day.”

The setup process took several hours because when the tools needed to be measured in the machine, the machine tool had to be stopped. For those in charge, it became clear: Dental Direkt needed to reduce idle times to allow expanded production times. This would then also lower the costs per part in the long run! 

They determined that the best way forward would be the purchase of a tool presetter, which allows the tools to be set outside of the machine tool and in turn, keep the machine tool running. They put out a call for tender to various manufacturers but ultimately decided in favor of a solution from HAIMER, the European market leader for tool holding technology.

End-to-end solution for shrink fit and tool presetting technology

The suggestion by Thorsten Böker, technical sales representative of HAIMER, was to invest in shrink fit and tool presetting technology. “This combination ensures the highest accuracy as well as a rapid and reliable presetting process,” describes Böker. “This saves approximately eight minutes per tool when retooling on the machine.”

Presetting yes, but why shrinking? The answer from Thorsten Böker sheds light on this: “As opposed to conventional ER collets, HAIMER shrink fit collets impress with excellent radial true runout accuracy and simple, quick tool changes. This reduces vibrations, resulting in improvements to the finished surface quality and the life of the tools. In addition, they have two contact surfaces so that they sit more precisely in the holder ensuring more rigidity and better runout.” The ER 11, ER 16 and ER 20 models of the shrink fit collets supplied by HAIMER can be used in existing ER holders and are compatible with standard ER clamping nuts. Their enclosed shape prevents coolant leakage and thus rules out contamination to the clamping cone.

Horizontal tool shrinking – ideal for small tools

Additionally, the shrinking process doesn’t take long, at least not for the HAIMER Power Clamp Nano NG i4.0 shrink machine chosen by Dental Direkt. Its horizontal design is easy-to-use, especially for smaller tools, and offers a 7" touch display. The intuitive software ensures simple, consistent operation. “As we place a lot of value on digitalization and end-to-end data flow in our manufacturing, we chose the i4.0 version of the shrink fit machine,” explains Röttger, head of technical sales at Dental Direkt. This HAIMER Power Clamp machine includes a hand scanner which reads the data matrix code on every shrink collet before the shrink fit process. It provides important shrinking parameters such as performance and time, which the intelligent NG motor coil automatically adopts. Finally, air cooling ensures contour-independent and reliable cooling of the shrink fit chucks and shrink fit collets. “One other important feature for us is the integrated length presetting function, which allows us to preset the length of tools and sister tools with repeatable accuracy to the hundredth of a millimeter,” adds Röttger.

Tool presetting at the touch of a button

Dental Direkt decided on a HAIMER Microset UNO 20/40 automatic drive for tool presetting. Thanks to fully automated tool measurement, this high-end model offers absolute operator independence and can be used with almost no prior practice. Jakob Röttger knows from experience: “Every one of us can operate the presetter after just half an hour of training.”

The company does not yet digitally transfer the measurement data to the lathe – but they are prepared for it. Data transfer can be carried out either via the integrated postprocessors or with a QR code and scanner. Operators of the Tornos Swiss-type automatic lathes currently use the printer integrated with the Microset UNO 20/40 automatic drive presetter, which outputs all tool-relevant data onto labels. This information is entered into the machine during machine setup. Röttger explains an important detail: “An offset value is stored on the presetter for every tool and the respective slot on the machine. This is calculated automatically so that precisely the right value is available when the tool is set up in the machine. This guarantees maximum quality and time savings, also for complex tools – just the way we imagined it.”

Röttger and his colleagues from the shopfloor are very satisfied with the newly installed complete system from HAIMER – which is made up of shrink fit collets, a HAIMER Power Clamp Nano NG i4.0 shrink fit machine and a HAIMER Microset UNO 20/40 automatic drive tool presetting machine: “It is just like our DD Solid Connect implant prosthetic system. There is nothing better than when all components come from a single source and fit together perfectly. The HAIMER system has made it possible for us to reduce our setup times by 50 %.”

Vai alla panoramica