Off-Line Programming System Cuts Programming Time 50 Percent

Backlogs began to play havoc with delivery times at Homeyer Tool & Die in Marthasville, Missouri. Herb Homeyer, company president, found the solution in the installation of a programming work cell in his shop. The purchase of a Torq-Cut vertical machining center (VMC) and FeatureMILL CNC programming software, both from Bridgeport Machines (Bridgeport, Connecticut), gave Mr. Homeyer the tools he needed to increase shop production volume by 50 percent, eliminate bottlenecks, and improve delivery times.

Homeyer Tool & Die builds tooling, supplies custom machines for the food service industry and provides welding fixtures, primarily to customers in the automotive industry. When the shop first opened its doors in 1990, it had just two Bridgeport Series Standard mills. The company grew rapidly over the next six years with the addition of seven Bridgeport EZTRAK combination (manual/automatic) knee mills and a horizontal machining center.

Homeyer's products, machined from tool and stainless steels, are quite diverse in size and features. Tool and die work and fixture lots of one or two parts are done on the Bridgeport Standard mills. The EZTRAKs handle small lot machining. Mr. Homeyer invested in a large, 20-hp horizontal machining center (HMC) for larger sized jobs. However, work requiring full CNC machining quickly became backlogged at the machine.

As part of his objective to expand the productivity of his CNC operations, Mr. Homeyer installed a programming work cell in his shop, featuring an off-line computer running FeatureMILL software. This Windows-based package generates NC programs for virtually any CNC mill.

Mr. Homeyer first learned of the potential time savings of FeatureMILL software from his distributor, C. J. Smith Machinery in St. Louis, Missouri. "The screens looked a lot like those on the EZTRAK control, and the operation seemed similar. During the demonstration, the software also seemed very user-friendly," says Mr. Homeyer.

Before implementing FeatureMILL, operators programmed the EZTRAKs and the HMC by manually inputting the data into the controls. While this procedure was fast and easy on the EZTRAK, this was not the case for the HMC. This relatively time-consuming method significantly cut into machine uptime, especially since the largest jobs consist of only 50 parts. Programming the machines for the many small jobs moving through the shop represented a great deal of non-productive machine time.

Learning to use FeatureMILL proved fairly easy. "Operators required only half a day of instruction by our Bridgeport representative before they were up and going. Now, the operators will get their machine running on one part, then go back to the work cell to program the next job," says Mr. Homeyer. Since its installation, the software has cut CNC programming times by 50 percent or more.

Customer-supplied CAD files of 3D wire-frame geometries easily download into the application, which translates data into machining information. Programs are downloaded from the computer to the RS-232 ports on the machines for direct-network control of CNC machining.

FeatureMILL deconstructs the part to determine a complete machining process, selecting optimum cutting tools and recommending machining sequences for both roughing and finishing. The operator reviews the tools and machining parameters on one screen, making changes as needed. This semi-automatic operation plays an important part in reducing programming time. A single click of the mouse button, and FeatureMILL uses the machining settings to calculate the tool path, then plots it graphically on the screen. The software can also generate tool lists and operation sheets automatically.

The Homeyer operators take advantage of the software's advanced capabilities to create macros, sub-programs and fixture offsets that simplify part programming. According to Mr. Homeyer, macros make part programs fast and easy. "We have one customer whose jobs require a bore with a counterbore in different locations in a plate. The operator can easily create a macro for this feature and then move it to different locations on the plate." A copy a function also allows operators to create multiple parts from a single part file. The macros and sub-programs also minimize program length and speed machining time.

In addition to the programming cell, Homeyer also invested in another machining center. "We were already familiar with the capabilities and ease of programming on Bridgeport systems. For that reason, we decided to go with Bridgeport for our second machining center," explains Mr. Homeyer. While visiting his distributor, he saw the Torq-Cut 22 VMC in operation and decided to get one.

Once the VMC was installed in the shop, Mr. Homeyer redirected stacked up work at the larger HMC to the Torq-Cut. While smaller, the VMC is said to be powerful.

The VMC did more than eliminate backlogs. According to Mr. Homeyer, the VMC increased shop productivity by 60 percent due to its easier programming requirements, compared to the HMC and the shorter learning curve. The PC-based control's use of shoptalk language and step-by-step prompting made programming easy for operators at a variety of skill levels.