So far all I've had to post about the SawStop Cabinet Saw is good news. Steve Gass knew, with the saws going out to hundreds of shops, that unusual behavior might turn up in odd shop settings. He has been listening closely to feedback from the field. I identified an odd behavior and was impressed with how quickly and proactively Steve worked to resolve it.
Setting: I work in an unheated garage shop. I often start winter worksessions around or below freezing. Things warm up to a light jacket level pretty quickly with the help of space heaters, the lights, my activity, and the tools.
Normal saw behavior: The blade brake stays active during coast down - the time between when you turn the power off and the blade comes to a complete stop. When running the green LED on the control panel stays on constant. During coast down this LED blinks. Do not touch the blade while the green LED is blinking, because that will release the brake.
How my saw behaved: The first couple times I would run the saw, particularly if run for short periods, the green LED would blink beyond the point when the blade had stopped turning. A person who did not notice that the LED was flashing could easily touch the blade and set off the brake when not needed. Oops! This behavior stopped after the saw had warmed up a bit, and did not interfere with my work. A note to people who use these saws and watch them very closely: it is normal for completion of the LED blinking to not exactly match the precise point of blade stop; the algorithm results in mismatch of up to 1 second.
First attempts at diagnosis: I think that SawStop had run the saws in cold temperatures but had not observed this behavior. They were very interested in figuring it out. At first they suspected faulty parts. Steve offered to have one of the owners visit my shop personally and check out the problem. I declined. A new electronic filter and control box were sent out. I installed them but it didn't correct the behavior. The good news was that my saw had been built to spec.
The solution: Steve Gass thought about the problem some more, and figured that the EMF signals that are monitored to tell when the motor has stopped might be getting confused with power pulses to the resistance heater than keep the brake cartridge at proper operating temperature. He reprogrammed a cartridge to shut down the heater during coast down. The cartridge, tested in my machine yesterday evening, seems to have solved the problem.
Next steps: I will sent my cartridges back to SawStop for reprogramming. That will take care of me. My guess is that future cartridges will go out with this revised program code, and that owners of saws in the field will be given the chance to have their cartridges updated.
I was not surprised that a minor issue came up, and think that SawStop handled it well. Steve Gass says that this is the only unusual behavior that has been reported since the December start of normal production.
Happy New Year to All,
Dave