Super-PID new low-cost router speed controller

[RomanLini]

Re; if running the motor at lower RPM can overheat it, the answer is both yes and no.

If you were to run the motor at 5000 RPM and full (applied) power, it would probably overheat.

BUT the Super-PID (being closed-loop) only applies as much power to the motor as is needed to maintain the RPM that you have set.

I've done some hours of cutting with the PID at low RPMs with no problems. For example, cutting acrylic with a 1/8" end mill at 2mm (0.080") depth and set to 11000 RPM, my router barely shows 15% to 20% applied power on the LCD, and as a 850W router that is under 170 watts being used. A 1/4" endmill in acrylic uses around 20% power.

Cutting aluminium at 14000 RPM with a 0.5mm (0.020") cut it is still under 25% power applied to the router, and at 14000 RPM the air cooling is quite good anyway, and the router barely gets warm.

I want to emphasise that you would not be able to use FULL router applied power at 5000 RPM, but that is such a slow speed for a wood router it would only be used for some special needs anyway - I have used for good result cutting low-melt polypropylene flooring sheet and polystyrene electrical boxes, at about 7000 RPM, both soft materials and only needing 10% or so of the router power so barely breaking a sweat.

An important point is that you can do a lot of cutting at lower speeds now (with the Super-PID) as it makes a lot more torque at lower speeds. So jobs you used to cut at 20000 RPM with reduced tool life, bearing life etc can now be cut at a more optimal 12000 RPM (for example) and prolonging both tool life and bearing life and giving a better cut. For anyone wanting to cut aluminium, plastics; acrylic or cheap PP, PE PS, etc this is a huge improvement.

There are some initial product specs up on Val's web site;
www.SuperPID.com
and I have PCBs on the testbench now and should be able to post a photo tonight.

[brtech]

I see this on the website:

Warning! The closed-loop nature of this motor speed controller means
that it is capable of delivering significant power to the motor during low RPM
use. At low RPMs the cooling ability of universal motors is reduced and we recommend
monitoring of the motor power and heat during low RPM use. We will not be held
responsible for damage to the router or to the Super-PID device caused by abuse.

If this is a concern, put a thermister on the router and monitor it with the microprocessor

[ger21]

Would it be possible to use one Super PID with 2 routers? Maybe use a contactor to switch power between the two?

[RomanLini]

brtech- I don't think it is a big concern, Like I said my router barely gets warm cutting most stuff at low speeds. I think the warning would be better to say something like "This will not turn a 30000 RPM router into a 5000 RPM spindle for milling steel!" or something like that. But it does give you quite a lot of usable power at lower speeds, many times more cutting power than you get from an open-loop router which is pretty much useless under 10000 RPM, and of course the benefit of the speed being fixed so you can tune around cutting resonances etc.

ger21- Sure it should not be a problem. You would need one relay to changeover the router power (2 wires) and another relay to changeover the sensor (2 wires). Or, you could just have 2 plugs and plug in the router power and the spindle sensor for the desired router. I just have an AC mains line plug on mine, and a 3pin small connector for the sensor.

It seems an unusual request, I'm guessing you have 2 routers set up and need to use both regularly?

Photo as promised.

Here is a shot of the assembled Super-PID product (with no case!) you can see the tacho display and the bar graph that shows how much % of power is being applied to the router. I faked the shot just using a 5 volt supply to get the display working, you can see there is no router attached yet or spindle sensor. I'm a lousy photographer and don;t have th elights etc to get a good shot in the workshop, this was taken in the sewing room (ahem).

The large metal square is the heatsink bracket, for light use this is enough heatsinking but for serious production use I would use a fan and/or more aluminium attached. The Super-PID was designed for serious use so I went with this system instead of the tiny cheap pre-stamped heatsinks.

There should be a couple of display colour choices too, currently I only have white on blue (which is good visibility) but Val has ordered samples in some other colours.

Anyway this photo shows pretty much what you will get as the working and tested product, it just needs a case and a few wires connected.

[CarveOne]

Cool! Looks really good.

CarveOne

[Khalid]

I am really impressed to see the Quality of the Product... I normally doing woodcarving and relief carving with my 25000 fixed RPM Router.. and It runs 8Hrs or more to accomplish a single carving..

I normally have to replace the bearings and lot of dull tools... This options will be great to reduce the Operating Cost as well as reduce noise..

I really anxious to see the final product and request to keep me in line for One Super-PID...

[adam_m]

Showing my ignorance here (not hard to do) but what's the difference between your speed controller and one that you buy off the shelf?

Adam,

[RomanLini]

Thanks CarveOne and Khalid! It's had a lot of work in development, seems like it's never ending.

adam_m- Good question! I'll try to put it in perspective;

Fixed speed router; Generally 25000 RPM to 30000 RPM, (like Khalid said), very noisy, lots of heat, tool wear and bearing wear and will melt plastic when cutting etc and can burn woods too depending on speeds and feeds.

Variable speed router OR any typical "speed control"; When you turn them "down" these just send less power to the router. So speeds are about 16000-30000 RPM range, and at lower speeds like 16000 there is very little torque. So if you are trying to use the lower speeds it will droop speed badly and have very little cutting power, or just stall, or speed will vary all over the place depending on cut depth etc. And under 16000 RPM you can pretty much forget about it, so you still get bad issues with melting plastic and aluminium melting onto the tool because you are forced to use too much RPM if you want to get any useful cutting power.

Super-PID closed loop speed control; This has a infra-red speed sensor pointed at the router shaft, so it measures the exact RPM of the router at all times. Then it uses a high-speed math algorithm called P.I.D. to adjust the power sent to the router, to keep the router spinning at the RPM you wanted. And it has an accurate tacho so you can set a chosen RPM based on speeds/feeds tables as people need for professional production.

So speed range is now 5000-30000 RPM, and you can get excellent power down to 9000-10000 RPM (used for most plastic and aluminium cutting etc) and even get significant amounts of usable power at the very low RPM range like 5000-9000 (where your router is almost silent!) that can be used to cut fussy materials like low-melt point plastics, fussy woods, and light cuts in materials for the purpose of getting good surface finish etc.

The idea of the Super-PID was to offer some (most?) of the performance benefits of a VFD spindle setup, but at a lower cost and an simple task of just connecting it to your existing router setup.

[adam_m]

Super-PID closed loop speed control; This has a infra-red speed sensor pointed at the router shaft, so it measures the exact RPM of the router at all times. Then it uses a high-speed math algorithm called P.I.D. to adjust the power sent to the router, to keep the router spinning at the RPM you wanted. And it has an accurate tacho so you can set a chosen RPM based on speeds/feeds tables as people need for professional production.
...

So, if I understand you correctly the PID creates low adjustable RPM with same power/torque?

Does that mean a traditional speed controller just cuts the power to the router to control the speed?

Adam,

[ger21]

ger21- Sure it should not be a problem. You would need one relay to changeover the router power (2 wires) and another relay to changeover the sensor (2 wires). Or, you could just have 2 plugs and plug in the router power and the spindle sensor for the desired router. I just have an AC mains line plug on mine, and a 3pin small connector for the sensor.

It seems an unusual request, I'm guessing you have 2 routers set up and need to use both regularly?

I'm building a router with 2 independent spindles. Two fixed speed routers and the Super PID would be about the same price as the two VS routers I was looking at.

[Boltz]

Hey Roman, I've been following you for a while and you do some really cool stuff!

Just curious, did you code the PID algos or is there something in the public domain?

Also, can you recommend any reading for those of us starting to climb the rather steep learning curve for PID?

Thanks, and keep up the good work!

-Jim Hart

[RomanLini]

So, if I understand you correctly the PID creates low adjustable RPM with same power/torque?

Does that mean a traditional speed controller just cuts the power to the router to control the speed?
...

I wouldn't say the "same" power at all RPM because the router naturally has a lot more power at high RPMs. But the Super-PID will increase the power to keep the RPM the same, so you can actually do cutting at quite low RPM (which is just not possible with a standard variable speed router).

And yes, traditional (open-loop) speed controllers just cut the power a bit and are only useful when in the router's sweet spot, ie quite high RPMs.

Ger21- Ahah I understand now. I would go for the 2 routers+Super-PID just to get the big performance benefits.

Boltz- Thanks for the compliemnt! And although I have put in a lot of work on open-source projects in the past (to give back to the world) and plan to still do so in the future, this particular project is a commercial one.

I have around 200 engineer hours invested in Super-PID so far and Val (the product owner) has a few grand invested in parts, production setup and lots more to spend yet on labour and advertising etc, so we need to sell quite a few of these to break even. And of course you would understand that means we would really NOT be wanting to help anyone compete. Some things are for giving away and some things are for making a living from.

And just while we are on the topic, this forum has specific rules about piracy of intellectual property and if anyone tries to hack/reverse engineer the Super-PID intellectual property I will be asking forum moderators to delete posts.