LMS 3960 or G0704 mill for a small lab?

[JimDawson]

Very true. I can probably get a IR thermometer from maintenance but I'm still nervous. I don't think Chris would send me a third board so I need to make sure I don't fry this one too. At what sort of temperature should I start to get worried?

I just looked up specs for a motor controller mosfet, the absolute maximum junction temperature is 150 C, it looks like normal operating temperature might be in the 70 to 90 C range. Based on that, if the heatsink is getting close to 100 C I would start shedding some load. I'm surprised that the controller doesn't have a thermal shutdown, most of the controller IC's have that built in.

This advice is my best guess, and worth exactly what you paid for it.)

another thought

Run it a medium speed, unloaded, for a while to get a base line reading. Then try it under a light load. Take severial readings under different conditions to see what 'normal' is.

 

[TIGL]

I just looked up specs for a motor controller mosfet, the absolute maximum junction temperature is 150 C, it looks like normal operating temperature might be in the 70 to 90 C range. Based on that, if the heatsink is getting close to 100 C I would start shedding some load. I'm surprised that the controller doesn't have a thermal shutdown, most of the controller IC's have that built in.

This advice is my best guess, and worth exactly what you paid for it.)

another thought

Run it a medium speed, unloaded, for a while to get a base line reading. Then try it under a light load. Take severial readings under different conditions to see what 'normal' is.

Thanks for the ideas. I ended up ordering the saw so I'll see how it goes. Hopefully the cuts I take won't have to be so small that it kills any time saved from not having to turn the whole thing to chips

 

[AlanR]

Thanks for the ideas. I ended up ordering the saw so I'll see how it goes. Hopefully the cuts I take won't have to be so small that it kills any time saved from not having to turn the whole thing to chips

In reality the cuts depend more on the table feed rates, slower feed, less spindle power. Do you have a power table feed on that machine? If you don't you should get one.

I just got a nice 1" arbor, so much better than the stepped ones. I thought about making one but I couldn't have made one as good as the one I bought, they're not cheap.

 

[kd4gij]

Get a good quality 1/2" roughing endmill. That should help you out.

 

[TIGL]

I am thinking about getting a power feed but do not currently have one. It would probably make this project much easier. I suspect I will need one when I move to the foot long version of this part

Get a good quality 1/2" roughing endmill. That should help you out.

I ordered two of these from McMaster along with the saw and arbor so if the saw proves impractical I'll use them