spindle vs router plz help

[mjs79]

hello

im in the planning stage of my diy cnc mill . i have my parts pretty much all picked out for my cnc mill ,some even on the way .im looking to use my mill for cutting aluminum and acrylic for my other hobbies im into .now i have come to a point where i dont think a router will cut it for what i want to do .
i was looking at a Milwaukee, 3.5 Hp EVS Router Table Motor , but for the money i think there maybe a better option for me .that being said what are my options for spindle/motor set up , if there are any for $500. or would the milwaukee be my best bet for the money .i have been searching the forum with little help for my question .
thanks for any info
cheers
mike

[turbotoys]

I would be interested to see if there is anything else out there as well- good question

[DonW]

There's a huge hole in the market for an affordable spindle for the hobbyist cnc market.

All you manufacturers out there, take note. If you build it, we will buy it.

Build one for $1000 or less and you could sell a ton of them.

[mjs79]

thanks for the info . i guess im going to have go with the router listed above and hope for the best .sounds like it time to hitt up a spindle maker with a group buy maybe then they would produce something we could afford.
cheers
mike

[harryn]

I am not sure if this fits your need or not, but I am planning to use the Bosch 1617 (I think that is the number). From various reviews, it had very low runout. No idea how it compares to your find - any info on it ?

[mjs79]

here is some info on the router
http://www.rockler.com/product.cfm?page=16977
http://jessem.com/motor.htm
hope that helps

[JRoque]

Hey Mike,

It also depends on other factors. I used a Porter Cable 3 HP router for a while and it did cut aluminum, acrylic and wood. However, depending on the precision of the cuts you want, that might not be the solution. My Porter Cable router has a 0.002" runout and I think this is typical. That was not good for my other purpose of cutting PCBs with it. Besides that, these routers run about 10K RPM or more which might be too fast for certain materials. The speed controls also don't lend themselves to automation as they are embedded in the router. Lastly, they are LOUD.

With these facts on hand, I decided to build my own spindle and drive it with a DC motor used in treadmills. My current motor is 2.5 HP @ 6750 RPM. I bought this at a surplus store and paid less than $75 for the motor and controller and then invested about $150 to build the spindle. The result is that I can cut pretty much anything from PCB to 1080 steel all at a 0.00005" runout and while being very quiet.

Again, the PC router, and many other wood router will cut acrylic (depending on speed) and aluminum if your machine is rigid enough and you're willing to slow down on some of the cuts. Some of the cheaper model routers that don't have a speed control onboard can be controlled with an external speed controller (about $20) and could be set up to be controller from your PC with a simple circuit.

If it were me, I'd go for a cheaper router to see if it works. Even a 2 HP router can cut the materials you mention.

Regards,
JR

[mjs79]

thanks for that great info , now you have me really rethinking my router plans .looks like i have more reading to do .
thanks

[Alex2005]

I am intending to cut steel with my build, so I have very much bulked my design up and have been considering a coolant system for the steel.

Would you say around 500-1000 rpm would be a suitable speed for low carbon steel, I know there are a lot of variables but a rough speed would be appreciated.

[mjs79]

. Some of the cheaper model routers that don't have a speed control onboard can be controlled with an external speed controller (about $20) and could be set up to be controller from your PC with a simple circuit.

what rmp ranges do these controlers run at ? say i have a router with 10-22k rpm , will i be able to do less then 10,000 rpm ?
could you provide some info on PC based controlers ?
thanks for you time and info !
cheers
mike

[JRoque]

Hey Alex. As you said, RPM depends on many factors. Newer mills are coming with highspeed motors these days. But that also assumes you're using the right tool and your machine is sufficiently rigid. I'd go for a slightly faster RPM than 1000 so you can make, for example, faster and shallower cuts or cut mild metals like aluminum. There have been good advancements in tool technology as well that let you run many times faster than you could before.

Mike, I don't have specific router model numbers at hand but if you want to run them slower than spec'd, check if they have a shaft mounted fan. These depend on the shaft spinning at a certain RPM to have sufficient air flow. An external fan may be installed to help - though cooling through body is the best and most efficient method.

As for the motor I used, here's a link: http://www.surpluscenter.com/item.as...tname=electric
It's a DC motor and it can be controlled with this: http://www.surpluscenter.com/item.as...tname=electric
That's not exactly the motor controller I have but it's similar and should work about the same.

To connect and control that from your PC, you need an isolation circuit.

NOTE: most SCR type of motor controllers (or ones that don't have a transformer) have a high electrical potential on their "ground" terminal. That means that if you touch the controller "ground" terminal, you'll experience a little over 50 volts going through you. Anything above 48V can be lethal. The same goes if you try to mate your controller's ground or negative pole to your machine ground. Be careful.

Back to the circuit. It consists of an optoisolator, a few resistors and a small signal transistor. I'm actually replacing mine with a Schmitt trigger version. Below's a quick snapshot of the diagram. I can post the CAD, CAM or g-code files after I'm done cutting it for myself.

Wow, look at all the typing above. I need to get here more often and write less each time

JR

[BobF]

Originally Posted by mjs79 . Some of the cheaper model routers that don't have a speed control onboard can be controlled with an external speed controller (about $20) and could be set up to be controller from your PC with a simple circuit. what rmp ranges do these controlers run at ? say i have a router with 10-22k rpm , will i be able to do less then 10,000 rpm ? could you provide some info on PC based controlers ? thanks for you time and info ! cheers mike

The inexpensive external speed controllers I have tried do not work very well. They have limited range and there is noticeable power loss at the router motor. The built in ones I have used (Makita and Milwaukee) work much better.