The second machine cuts (even) better
The real prowess of a machine tool manufacturer is only revealed in truly difficult jobs, such as a “flying” change: Schmedthenke Werkzeugbau ordered a second Droop+Rein milling machine with overhead gantry (Droop+Rein FOGS), which began operation at the same time as the other FOG machine shut down for retrofitting.
It was an investment they haven’t regretted, according to Jörg and Carsten Schmedthenke, Managing Directors of SWB Schmedthenke Werkzeugbau GmbH in Gütersloh. Having begun to smooth large tools, the workshop has become a highly sought-after specialist in large sophisticated tools for automotive bodywork. Jörg Schmedthenke looks back: “We weren’t able to smooth large components in the past, because we didn’t have the right machines.” In 2012, the family operation therefore took on a second-hand Droop+Rein FOG 2500 from the BMW toolmaking facility in Eisenach (pallet: 236 inches × 98 inches, three-way pallet changer, changer for 60 tools, fork head with three motor spindles, maximum 24,000 rpm), which BMW had already comprehensively retrofitted.
“We have been able to expand our range to include very large structural and exterior body parts” says Schmedthenke. “Today we take on a lot of smoothing work not only for our own products but also for external clients. This means the investment we made in the Droop+Rein FOG 2500 has more than paid for itself.” In 2017, the machine underwent another retrofit, in which the golden oldie (built in 1994) was given new drive technology and a new control system, meaning it can now machine parts from high-alloy castings. According to Schmedthenke, the machine has smoothed “sensationally” since the retrofits.
“Shortly after commissioning, availability was already at over 95 %.”
Jörg Schmedthenke, Managing Director of SWB Schmedthenke Werkzeugbau GmbH in Gütersloh: “We have been able to expand our range to include very large structural and exterior body parts, thanks to the new Droop+Rein FOGS 40 68 C. Today we take on a lot of smoothing work not only for our own products but also for external clients.”
In 2016 – thanks to the enormous success of the old Droop+Rein machine – the East Westphalia-based company ordered a second one: The Droop+Rein FOGS 40 68 C is also a five-axis machine tool designed for smoothing (X axis: 268 inches; Y axis: 157 inches, Z axis: 59 inches, C axis: ±200°, B axis: ±115°; pallet: 236 inches x 98 inches, changer for 51 tools, fork head with two motor spindles, 10,000 rpm or 20,000 rpm) with a Heidenhain control system that is tried and tested in toolmaking (iTNC 530 HSCI). “With the second machine, we’re smoothing all of the components for the automotive sector,” explains the Managing Director. “The investment in a second FOGS machine also provides more security in the event that one machine fails.” Indeed, the new Droop+Rein FOGS took over the work of the first machine when it underwent 22 weeks of planned downtime for retrofitting.
Effective smoothing: The Droop+Rein FOGS 40 68 C is a five-axis machine tool designed for smoothing and is equipped with a Heidenhain control system that is tried and tested in toolmaking (iTNC 530 HSCI).
“It was very important for us to have a supplier on whom we could rely completely in terms of meeting deadlines and commitments”, says the Managing Director. “We agreed on a nine-month delivery time, and Starrag met this 100 %.” Equally important to the East Westphalia-based company was a very high level of availability, which was at over 95 % shortly after commissioning. This reliability was not only thanks to the FOG series but also, according to Schmedthenke, down to the Starrag staff, who “were extremely knowledgeable and paid close attention to detail, down to the last 100th of an inch” during assembly. In line with the Starrag claim “Engineering precisely what you value”, Schmedthenke thus received a machine with all the features they wanted exactly when they needed it.
Carsten Schmedthenke, Managing Director of SWB Schmedthenke Werkzeugbau GmbH in Gütersloh, has never regretted the purchase of the first, second-hand FOG. Together with brother Jörg, he therefore ordered a second, new Droop+Rein FOGS 40 68 C milling machine with overhead gantry.
This meant it went into reliable operation four weeks after setup, precisely when the Droop+Rein FOG 2500 was due to be shut down. The machine wasn’t pre-assembled at the Starrag factory in Bielefeld, but built from the ground up in Gütersloh and put into operation. The mechanical structure was so accurate that only the smallest of optimisations to the geometry was necessary. “The machine geometry was almost faultless immediately after setup”, says Schmedthenke happily. “And with a lot of other manufacturers, the geometry can’t really be assessed, because their machines have to be significantly adjusted straight away.”
Versatile application: With the second FOGS 40 68 C, Schmedthenke is smoothing all of the components for the automotive sector.
The East Westphalia-based company is now using the second machine purely for smoothing. “With an additional drive, we could also use it for roughing”, emphasises the qualified engineer. “But because of our two-machine strategy, we’ve decided to employ a machine just for smoothing. The precision needed in toolmaking can only be achieved by roughing on one machine and smoothing on another.” For quality reasons, the company from Gütersloh does not conduct all of the machining in one clamping operation. During roughing, so much heat is transferred into the component that its geometry changes. Schmedthenke: “If I were to start smoothing immediately, the dimensions would ‘run away’ from me as the component cooled.”
In waiting: Schmedthenke allows tools to cool off and relax for two to three days after roughing, before they move to one of the two FOGs for smoothing.
"The investment in a second FOGS machine also provides more security in the event that one machine fails.”
In order for tools – for example for the outer shell of vehicles – to achieve milled perfection, Schmedthenke allows large components to cool off and “relax” for two to three days after roughing before they move on to smoothing. “It means we have to work quickly today, but it’s only if we allow the tool a couple of days’ rest that we will achieve the desired level of precision” explains the specialist. “And the benefit of this precision can be seen in the short training period needed for the press.”