[dwacker]

I use a Rigid branded laminate trim router. It is variable speed with soft start. I have the understanding that I can NOT use a speed control with this router. I'd like to slow it way down for plastic. Does anyone know of a safe way to do this.

Don

[dburley]

I have the same Rigid trim router and I'm presently building a CNC system to use it. Most speed controls operate by chopping the AC current at some point on the sine wave and I think thats why Rigid says not to work another speed control with it in series. However I thought this did not rule out running on reduced voltage such as when a variact is used. I happpen to have a large 30 amp variact and I just now tried that method. I was very surprised because there was hardly any change until the voltage was cut down to about half. Then some slowing but NO power. The other strange thing was that when going over the normal 120 volts to about 140 which the variact allows, the Rigid's speed actually dropped somewhat. I would guess that the Rigid uses a micro proccessor to control the speed and soft start feature. Thats the only thing I can think of that would provide that kind of
control with reduced voltage. We are both going to have to figure other ways to cut plastics.

Dave

[Oldmanandhistoy]

Try single flute cutters effectively halving the spindle speed.

John

[dwacker]

We are both going to have to figure other ways to cut plastics.

Dave

I would like to avoid having to mess with my z axis and mount. I'm going to run and measure the Ryobi and the Rigid at Home depot. They look the same, if so I'll just pick up the ryobi and use a real speed control. I can cut cast acrylic just fine with the rigid but extruded or abs is just a complete melt down.

Thanks
Don

[arturod]

Don,

I have just release a new speed control that is suitable for routers. Take a look:

http://www.cnc4pc.com/C18-Pot_Driven...trol_Board.htm

It can be used to replace the pot on those Chinese speed controls so you can control speed directly from your gcode.

Please let me know if you have any questions.

Thanks,

Arturo Duncan
http://cnc4pc.com

[dwacker]

Don,

I have just release a new speed control that is suitable for routers. Take a look:

http://www.cnc4pc.com/C18-Pot_Driven...trol_Board.htm

It can be used to replace the pot on those Chinese speed controls so you can control speed directly from your gcode.

Please let me know if you have any questions.

Thanks,

Arturo Duncan
http://cnc4pc.com

Well that I like. So all I do is open up the Rigid and solder two wires, maybe drill a hole to feed them through and thats it? Where is it that I connect to the PC for mach3 control? Have you verified that it works with the Rigid variable speed control?


Sound very cool
Don

[Oldmanandhistoy]

Don,

I have just release a new speed control that is suitable for routers. Take a look:

http://www.cnc4pc.com/C18-Pot_Driven...trol_Board.htm

It can be used to replace the pot on those Chinese speed controls so you can control speed directly from your gcode.

Please let me know if you have any questions.

Thanks,

Arturo Duncan
http://cnc4pc.com

This sounds to be similar to an idea ger21 has talked about some time ago now. I liked his idea and have planned to have a go myself but as yet not got around to it.
Basically it was to just use another small stepper motor and drive to turn the speed adjuster on the spindle. Would be quite easy to implement and cheap also for parts.

He’s a smart bloke that ger21

John

[arturod]

Don,

I have not tested it with the rigid speed controller, but it should work. There are two ways of doing this:

Method 1:
1. Open the router and measure the impedance the current pot is using.
2. Use this guide for selecting a parallel resistor so you can set the total impedance of the circuit equal to what you currently have. http://www.cnc4pc.com/Tech_Docs/Replacing_pot_guide.pdf
3. Then proceed to rewire as you described.

Method 2:
1. Get a commercial speed controller, like this one: http://www.harborfreight.com/cpi/cta...emnumber=43060
2. Replace the connections on that speed controller, which is a proven thing.

You could leave the pot on the speed controller and use it override the speed been instructed from the PC, but keep in mind that if you do that you would only be able to reduce the speed to ½ of what you normally would.

Thanks,

Arturo Duncan
http://cnc4pc.com

[dwacker]

I guess that bring me back to th origonal problem. What happens when you do this with the soft start motor? Will it be damaged?

Don

[frostfrank]

If this is just a replacement for the manual pot on the router does it allow reduction of the speed below the original pot? If router speed cannot be reduced below original it does not answer the first question.

[arturod]

Don / Frank,

I do not know enough about soft start motors, but I have never heard about a problem using the chinese speed controllers with motors with soft start. These chinese speed controllers work very much as a VFD, the main difference with VFDs, is that they do not rectify the current before creating the new frequency. This creates a very obnoxious wave form. That is why usually these speed controllers do not reduce the speed to less than 50%. This answers Frank’s question. Yes, if you reduce the resistor or pot value you could go lower, but I would not do it if I where you.

I know a lot of people have bad things to say about these speed controllers, but they do work for most users.

Thanks,

Arturo Duncan
http://cnc4pc.com

[dwacker]

I tried my mlcs router speed controller, no luck the motor will not even start. I grabbed one from harbor freight, same deal motor does not run.
I guess I'll go measure the ryobi then get controller to change the rpm in mach3.

Thank for the help

Don

[low_48]

I think a different chose of router bits would eliminate the plastic melting. Use a Onsrud c flute for plastic. You won't believe how clean they cut. You may check on recommended speeds, but they should work alot better.

[dwacker]

I think a different chose of router bits would eliminate the plastic melting. Use a Onsrud c flute for plastic. You won't believe how clean they cut. You may check on recommended speeds, but they should work alot better.

Those are what I'm using. I can get a clean cut at about 12K max but thats with my regular router that has a speed control. Unfortunatly the rigid will not go below 20K.

Don

[Oldmanandhistoy]

I still think that ger21’s idea is good to go and when I get the time I will have a go.

John

[ger21]

I'd buy Arturo's ready to run solution rather than build it from scratch.

[dwacker]

I got this one figured out. Called onsrud hoping for another bit that would cure the problem. They suggested the same bit and that my thinking was backwards. I ran the speed up to 30K and am getting great cuts.

Thanks for all the suggestions
Don