PM Core Road Automated Tooth Form Grinding

Two core rods were presented to the CNC grinder for tooth form grinding. Both were ground to a tolerance of within 0.0001" per side (within 0.0002" OD measured over pins). The process was nearly completely unattended and was set up by a technician who had never ground this type of tooling before. It's a nice example of applying the correct new technology to revolutionize an age-old grinding process.

The core rod was a 48-serration rod with a simple 90° included angle with sharp corners. It was 12 inches long by approximately Æ0.900" at the grind area. The grind length was 3 inches. The core rod material was hardened M2.

The successful demonstration was performed for a mid-sized manufacturer of tooling for the pressed metal industry. This manufacturer utilizes state of the art CNC technology in virtually all of their manufacturing except for the area of punch grinding. Skilled grinder hands dress form into wheels manually and plunge grind them into the core rod until re-dressing is required. The process is repeated painstakingly until a punch is completed. The quality of the punch is operator dependent.

With the CNC process, the serrated rod was rough and finish ground. The base machine was a Amada Wasino MeisterPro 2 Axis CNC Surface and Form Grinder equipped with a Nikken CNC rotary table. The MeisterPro is equipped for wheel form dressing and automatically re-dresses the wheel form while in an unattended grinding cycle.

The system includes a graphical conversational operation system that allows the operator to load programs (Ethernet and serial interface available) or manually input the form of the wheel. For simple wheel shapes, a unique dressing screen allows direct input of angles and radii. It took less then a minute to input the wheel shape for the 48-tooth core rod.. The grinding wheel form and the dresser is graphically displayed on the monitor as it dresses.

The existing processing for these core rods requires highly skilled, experienced tool grinders. This manufacturer utilizes a panagraph dresser for dressing. Much of the process time involves the re-dressing and re-qualification of the wheel after each dress. The company's staff indicated that this was a very difficult core rod because of the multiple dressing requirements to maintain a sharp corner in a 48-serration punch.

The automated process demonstrated by Amada Wasino turned the re-dress and qualification into a totally unattended and compensated machine operation. The ability to automatically re-dress and accurately compensate allowed the maintenance of the sharp corner. Forty-eight "V-formed" slots were ground with sharp corners (R0.002" max) with per side depth repeatability of within 0.0001".

The company's grinder hands were very impressed with the MeisterPro's accuracy and ease of operation. The company's management were very impressed with the processing time. The total processing time was 3.5 hours including setup time. This included nearly three hours of unattended grinding (70 minutes roughing + 90 minutes finishing).

This company's typical manual processing time is anywhere from 12-16 hours for this type of core rod. This represents a four-fold increase in productivity in the grinding area. In addition, the most highly skilled grinders are freed for other productive tasks.

The MeisterPro has a proven track record in high precision mold and die tool rooms and production facilities in the US and worldwide. The common requirement for all installations has been unattended grinding accuracy with automatic dressing, ease of operation for toolmakers, and speed. These proven capabilities provide an excellent machine for automating the grinding of PM punches, core rods, splines and broaches.