Where to get started with motors

[hotrdd]

Though I’m going to have a ton more questions as I progress I’m wondering if someone can help guide me in the right direction with looking for motors. I’m building a large 4’ x 8’ table that will be used to router shapes into wood and cut out panels. Hopefully it will also be able to handle some shaped molding. “SUPER” precision and speed are not a hug issue here as most of the pieces are just one off. I can use the down time to get the next one programmed. I’ve been reading up on converting a DC motor to a Servo Motor and am wondering if this is worth pursuing?

Please treat me as an absolute novice, what HP etc should I be looking at? I come across a lot of equipment in my work and am wondering if I can keep my eye out for something? What questions do I need to answer first? Would a treadmill DC motor with gear reduction work?

[erase42]

Well for something to start with, you probably dont need a motor with a gear reduction built into it since the mechanics of your machine will introduce some sort of reduction and most gearboxes are of a low precision design thats not good for cnc. For instance, your leadscrew and nut will cause some reduction, and any toothed belt system used to connect motor to moving part would again involve a reduction. While it is possible to convert a standard motor to a servo, either AC or DC, there are so many pre-engineered units out on ebay etc., that making your own is just adding a step of uncertainty and possible malfunction( headache). IF you say speed isnt a huge issue, you might look into using larger stepper motors, somewhere up in the 450oz torque range. Read some of the posts here and ask some questions about cutting speeds and such that people are getting with steppers.
Stepper motors as well as the drivers are usually much cheaper than servos, more commonly available and simpler to hook up. Usually the accuracy of steppers is by far good enough for woodwork. Steppers will be a little slower (mostly just on high speed transit moves) and noisier for the most part( at some speeds), while servos run faster and quieter. Steppers do not need to be tuned other than setting acceleration speeds. Servos require tuning so they can work properly with your load and speed ranges. Servos also require the extra wiring of encoders etc, that present more connections for problems like bad plugs and connections due to vibration, or failure of the optical encoder due to dust or other harsh conditions. Do a search on ebay for servo motor and stepper motor and see whats out there, also visit some of this sights sponsors and before long you will know exactly which way you want to go with it. If you have any more questions, please fire away.