Every manufacturer is faced with the decision at some point: is it time to upgrade equipment and expand my capabilities? The real question, however, is how soon you’ll begin to realize a return on that investment, which is often tied to efficiencies leading to a reduction in the time it takes to manufacture a part. Here’s how Siemens and Reishauer helped one gear manufacturer to achieve just that, and more.
Relying on Reishauer
Custom Gear & Machine is a full-service gear manufacturer, producing spur and helical gears to AGMA 8 thru 14 standards and up to 30” diameters typically, plus splined shafts to 54” in length. Its customers include many of the leading builders of agricultural equipment, construction, and off-road vehicles, machine tools, printing presses, food processing equipment, overhead cranes, materials handling devices, lift equipment, process equipment such as large water pumps, and more. Founded in 1994, the company specializes in lot runs from a single piece to 500, and it works primarily in steel bar grades including 4140, 4150, and 8620. The shop is know for its work in forgings, as well as cast and ductile iron, brass, bronze, and aluminum, per its customer’s requirements. Custom Gear products are often used in gearboxes and transmissions by equipment builders or their primary tier component suppliers.
Seeking to achieve maximum efficiency and reduce production time, the company recently decided to make a capital investment involving both Reishauer and Siemens. “We were looking to expand our gear grinding capability, and the Reishauer RZ400 offered us many benefits,” according to Tim Rose, vice-president of manufacturing, who runs the business with co-owners Dave Patterson and Mike Rasmann. “They include 400mm OD, 10mm root diameter, up to 999 teeth capability, helix angles to +/- 45º and a z-axis of 300mm—all features we could use on a daily basis. We also liked the easy access four-door configuration and serial interface, plus the machine’s auto wheel dresser and add-ons of materials and part handling devices.” Fig.1(http://www.gearsolutions.com/media/uploads/assets/Images/figures/May_11/0511_Siemens_Fig1.jpg)
Custom Gear & Machine was already running an older Reishauer grinder, but it was seeking to improve its throughput and overall grinding department performance. The RZ400 fit the ticket, and on one job the cycle time dropped from 40 minutes to only six minutes. The machine has three features in particular that helped achieve this. It has more than double the surface speed than the older model, going from 1,900 to 4,000 rpm. It also had a seven-start grinding wheel versus a single-start variety. And, with a coolant pressure increase over previous machines from 30 psi to 300 psi, the flushing and grinding integrity has been radically improved.
During the purchase Custom Gear & Machine was assisted by Dennis Richmond, vice president of the Reishauer Corporation. Richmond describes his relationship with Custom Gear, and with Siemens as well. “Our previous gear grinders at Custom only allowed them a 13” diameter, and they were looking to step up to a larger 16” maximum diameter, plus they were seeking other features we were able to offer,” he says. “We use the Siemens numerical controls on our machines for a variety of reasons, especially the architecture’s ability to allow our engineers to customize the front ends. This simplifies the addition of new part programs and helps operators more easily navigate the programming and setup. When the data input is completed for the current screen, for example, the operator is prompted to enter data for the next screen and so on until the program is completed.”
Rose confirmed this point, adding that Custom Gear’s machinists are each responsible for the setup, running, and maintenance of their machine. “They take real pride in making sure the jobs are done right and that the machine is always in great shape,” he says.
One of the current machinists running the Reishauer RZ400, Daniel Warren, noted that he had not previously run a machine with a Sinumerik CNC from Siemens onboard. “I got great training from Reishauer and was up to speed very quickly,” he says. “We were making parts within a few days after the installation, and I was completely comfortable with the easy operation of the CNC in less than a month.” Figure 2(http://www.gearsolutions.com/media/uploads/assets/Images/figures/May_11/0511_Siemens_Fig2.jpg)
In describing the automatic wheel dressing sequence, he also noted how the CNC automatically adjusts the settings to compensate for the reduced wheel diameter after dressing, bringing the wheel to the correct point of contact with the subsequent workpieces.
Systems by Siemens
Data such as gear configuration, fixture design, and all tool settings are entered into the screens, including pitch, pressure angle, teeth, and dressing steps. Once a new part program is completed, the operator can begin working through the “man/machine interface” (MMI) setup screens designed by Reishauer, which also function in the same manner. Reishauer further allows its customers to add their own HMI screens for features onto the Siemens CNC for data acquisition, training aids, and even SPC protocol operations. This service enables the customers to have a common look across the screens on many machines in their shop. This is especially helpful in work cell setups, where a single machinist is running multiple machines. Figure 3(http://www.gearsolutions.com/media/uploads/assets/Images/figures/May_11/0511_Siemens_Fig3.jpg)
Reishauer harnesses other aspects of the Siemens product and service package for added functionality, including motor and drive packages, in building the control structure on its machines. This allows a seamless integration between all drives and the numerical control unit (NCU), according to Richmond. It also makes a much easier task of integrating ancillary machine devices such as chip conveyors, filtration systems, wheel dressing stations, and especially the critical materials handling and part loading devices frequently built with its machines for customer work cell setups. Siemens makes use of the Profibus networking protocol, enabling Reishauer to link various control devices and other machine tools together, thus greatly reducing the field work integration and wiring time during installation. Reishauer uses Profibus to link the onboard Siemens Sinumerik 840D CNC to VFDs, other drives, electronic gearboxes, and balancing systems for the grinding wheel on its machines.
Mike Rasmann, co-owner and vice president of operations at Custom Gear, says that “Our investment in the new Reishauer gear grinder has expanded our capability, allowed us to produce more parts for more existing customers, and even opened some new business doors for us. With the added benefit of increased safety on the machine, it was a win-win situation for us all around.” Figure 4(http://www.gearsolutions.com/media/uploads/assets/Images/figures/May_11/0511_Siemens_Fig4.jpg)
Rose agrees, adding that “It’s a great machine. When we have any need for assistance, including parts and especially application engineering, we know the answer is just a phone call away,"he says, "Reishauer has been there for us on many occasions. This is a big reason we’ve done business with them for 15 years, and will continue to do business with them in the future.”
Custom Gear also operates a full machine shop with four-axis vertical machining centers, horizontal machining centers, sawing, and broaching equipment, plus a full turning machine department, capable of handling 29” diameter and 72” long workpieces. Its quality department boasts CNC gear inspection machines and CMM capability. Rose notes that many of the machinists at Custom Gear have more than 20 years in the business, most of them with his company. “We’re a real family here,” he says, “and you can’t put a price on the value that brings to our company. And, by extension, to our customers."
