Simple controls for complex work
- June 8, 2003
Managing simultaneous three-spindle operation on a deep hole gun drill machine
Retrofitting the deep hole gun drill machine with two new controls
An Ontario hydraulic press manufacturer’s three-spindle deep hole gun drill machine gets a makeover to improve machining efficiency
Manufacturing large, heavy hydraulic presses with 20 to 30 ft long plates requiring 50 to 60 deep holes requires skill, industry know-how and the right equipment.
Dieffenbacher North America, an OEM manufacturer with a 55,000 sq ft (5,110 sq m) machine shop in Windsor, ON, that has serviced Canada, the US and Mexico for the past 35 years, has always had the skill and industry know-how. It also has had the right equipment, but recently upgraded a deep hole gun drill to improve manufacturing efficiencies.
The deep hole gun drill, capable of producing 9 ft (2,800 mm) deep holes, can handle parts up to 60,000 lb (27,000 kg). The machine was originally designed by Dieffenbacher Germany in 2004 and built at the Windsor facility. It replaced a much smaller machine that was in use at the time. The machine must drill approximately 50 to 60 holes on one plate and mill the associated pockets around the holes. It takes roughly 30 minutes to drill one hole, so finishing a press plate typically takes approximately 30 hours.
Nick Lupulescu, plant manager for Dieffenbacher North America, says the company wanted to improve production times for the press plates. It developed a novel three-spindle design to machine three holes simultaneously.
“The three spindle design is for increased capacity. Now we can drill three holes at the same time. One drill unit is adjustable for height and if needed, can drill a hole at a different height at the same time. The ability to mill the pockets and slots, and simultaneously drill with three spindles at the same time provides us much efficiency.”
To get the machine to drill three holes simultaneously though required controls for the spindles and the associated programming update. Dieffenbacher called in Cybertech Controls & Electric Inc., a machine retrofitter in Windsor, ON.
“One of the challenges was handling the different feed rates of the three different axes,” says Dave Allen, who co-owns Cybertech with partner Joe Carroccia. “It’s very difficult to set up a control and programming because you have one override on the CNC and when you program three axes at a certain depth, they all go at the same feed rate. We had to make two of the PLC control axes with separate overrides and we also had to set up separate spindle overrides for each of the three spindles. We really had to do some very complicated PLC programming to make this happen.”
The project was completed in two scheduled phases over a two-year period adds Lupulescu, because first, Cybertech had to take a manual machine and convert it into a CNC for two spindles. When Dieffenbacher added the third spindle, Cybertech came in to set up the controls for it and then created the program allowing the three spindles to operate simultaneously. From Cybertech’s end, setting up the first control took about two months and the second phase, took approximately one month.
Cybertech selected Heidenhain controls. To achieve the complex programming it used two controls, the iTNC 530 and the TNC 320.
“The TNC 320 controls the process used to mill the pockets in the press plates as the machine is drilling deep holes via the use of the iTNC 530. We set up the overrides for each of the three spindles and connected the two controls via an RS232 interface to fool the machine into operating all simultaneously,” explains Allen.
The gun drill is now programmed so that when the whole plate moves, that movement is transmitted to the TNC 320 and does an automatic offset, adds Allen.
To simplify the complex programming, Cybertech created custom OEM cycles for the controls, which the Heidenhain controls allow for, and which makes these controls a top choice for Allen. “I’ve worked with every control that is out there and I like the Heidenhain for this kind of complex programming. I would have had a tough time doing what we did at Dieffenbacher with another control. The control offers very powerful PLC programming capabilities and the way to debug issues is also very good,” says Allen.
Lupulescu adds that Dieffenbacher wanted the Heidenhain controls “from the beginning.” SMT