Not a new technology (Oriental Motor has the Alpha-Step series, for example), but there is a talk of a retro-fittable feedback /drive system at an economical price, within a year or so.ġ0. Geckodrive has a drive under development that will pull more power out of a stepper motor if it has an encoder (ala servo motor). Consider getting motors with rear shaft extensions, so that encoders could be fitted. Belt reductions give the fine resolution without backlash.ĩ.
![deskcnc full version deskcnc full version](http://speed-new.com/wp-content/uploads/2015/11/34536345346.jpg)
It will not pass for fine precision clock-making (but then you shouldn't be looking at a MechMate anyway). The "first option" geared motor above has an acceptable backlash for general board cutting and cabinet making work. If looking at a motor already integrated with a gearbox, watch out for the backlash. Very low inductance motors cannot be driven properly by Gecko's, while very high inductance motors need very high voltage drives that are not easy to obtain.Ĩ. For Geckodrives, the inductance must typically be somewhere between 1.5 and 6mH. If you want the motor to be compatible with a certain range of drives, the motor inductance must match. To wire a motor half-coil, it must have 6 or 8 lead wires.ħ. (this gives the most torque at high speed while keeping the motor temperature within limits). The best wiring configuration for our router driving application is "half-coil". The shafts must be at least 32mm long to reach the rack, but not longer than 40mm otherwise they will collide with the rail supports.Ħ. For the MechMate mechanical design, the motor shaft must be at least 12mm in diameter to carry the spring load and not bigger than 14mm so that a small pinion gear can still be fitted. Avoid motors much longer than this - see point 3 above.ĥ. When used un-geared, you will need a double-stacked motor at about 96mm long. For geared (or beltdrive) motors, a single stack (motor length about 66mm ) is enough. Nema34 motors are available in different lengths, depending on whether the rotor magnetics are single, double or triple stacked. Besides, bigger motors bring other problems ().Ĥ. Do not be tempted to use bigger than Nema34 motors - they will not fit the standard mountings provided for in the design. Use at least a Nema34 size, meaning that the square body is 85x85mm. Only consider a square body motor - the round body motors are older technology with a lot less torque.Ģ. You will be spending a little more time on sanding the slightly rough edges of your cuts though. Even before adding belt reductions, you will have an income producing CNC router. One of these inexpensive motors, with a belt reduction added at a later stage, will rival the performance of the "first choice" geared Oriental Motors mentioned right at the top. The price over there, without shipping/tax charges is under $60. MotionKing () 34HS9801 () is being used happily and can be imported direct from China. Third choice is still to use an un-geared Nema34 size stepper motor directly driving the pinion on the rack, but to go for something much less expensive than the premium "Oriental Motor" brand. If you want to go this route, the Oriental Motor Vexta-Step type PK299-F4.5A () is probably a better choice than the PK299-01AA that I used before. The smallish price difference does not make an un-geared Oriental Motor attractive, unless you want to start out with a well-known motor to add a non-backlash belt reduction () later. Still produces a very passable CNC router.
![deskcnc full version deskcnc full version](https://i.pinimg.com/originals/6d/35/d3/6d35d3b3ff3368d4bb7c3de774e0efef.png)
Less expensive than the first choice geared motors, but less shaft torque and a slightly rough cut quality. Have past personal experience with Oriental Motor Vexta-Step type PK299-01AA () motors ($205). Second choice is to use an un-geared Nema34 size stepper motor directly driving the pinion on the rack. The equivalent motor in Europe is the Oriental Motor PK296AE-SG7.2 () It works well with Geckdrives () 201,202,203,250,251,540 However, it is an expensive motor, and difficult to obtain outside the USA. Most MechMate builders use this motor and are happy with it. It is the Vexta-Step type PK296A2A-SG7.2 ():
![deskcnc full version deskcnc full version](https://www.cnccookbook.com/wp-content/uploads/2012/08/HobbyCNCControlShare.jpg)
Today's (Nov 14, 2008) first choice in motor is a geared stepper motor from Oriental Motor Corporation available as a simple secure on-line purchase at around US$250. The earlier version of the thread is archived here (). A number of posts in this thread were edited and/or deleted Nov 14, 2008. There has been some evolution on this topic.