What electronics?

[Michael In Cali]

OK, next question? We need stepper motors and driver boards.

I believe Bob used a xylotex stetem. They sell the board, 24V power supply and 3 269 in-oz steppers for $380. This is a bipolar driver board, and I understand that bipolar is prefered to unipolar (but I can be corrected). 1/1, 1/2, 1/4, 1/8 microstepping. 2.5 amps at 35 volts. (why not 36 volts like the power supplies you can get?)

Then, of course, is the popular Gecko 4 axis controller which goes for about $250 without the steppers. vast microstepping options. 3.5 amps to 50 volts.

There is also the HobbyCNC board which you have to solder yourself. Cheap at $67, $260 with 200 in-oz steppers. Unipolar only. 1/1, 1/2, 1/4, 1/8, and 1/16 Microstepping. 3.0 amp 36 Volts Maximum.

Lastly and cheapest are the various Chinese Toshiba chip items that are quite attractively priced, even with overseas shipping. Some as cheap as $200 or so. Similar microstepping and maximum current as the above units.

So, which way to go? I might be cheap, but I hate paying twice and don't like getting shafted by overseas people who just won't deal with you if there is a problem.

[kemper45]

Michael,

I went with the "3 axis package" deal from cncrouterparts.com which includes :

- 48V 7.3A switching power supply
- Gecko G540 4 axis stepper motor driver
- 3 High-torque Nema 23 380 oz-in stepper motors. These motors already have the current set resistors installed in a pro-grade metal shell. No soldering or crimping required. These are optimized for the G540. These motors use all of the 3.5A the G540 has to offer.
- 3 High-performance flexible motor cables: (1) 6'and (2) 12' cables

I also bought the parallel cable to connect the driver to the computer

My reason for doing so was my desire to get an all in one system without the need to solder a board or construct cables to connect motors to driver. Admittedly not the most economical solution but I was OK with the added costs to the overall project.

Keep these posts coming as we all benefit from the interaction.

Dave

[groswald]

I also went with the CNCRouterParts 3-stepper Gacko-based kit. A bit more expensive, but seemed worth it for reasons similar to those Dave provided.

I did forget the parallel cable. I hope I can find one in my box-o-cables!

Randy

[kemper45]

Randy,

Funny you mentioned forgetting the parallel cable as I did the same thing and had to place a second order for it. From research I have done you need to be careful with the cable - "ordinary" parallel cables used for printer connections won't always work. Something to do with not all pins are wired from one end to the other I think.

Dave

[groswald]

Dave,

Good point. You are right, most printer cables used just a few of the available pins. I guess I will have to place another order too!

Randy

[Michael In Cali]

Lets beat on this some more...

Either confirm my position or talk me into spending more money.

Hands down, the cost winner for suitable electronics is EBay a matched system from China. Longsmotor (of which there seems to be a couple on e-bay) sells a 270 or so in-oz 3 axis system with 4 motors, combo BOB/Driver board, and power supply for $210 deliverd to the states.

Thats cheaper than just a Gecko G540 by itself.

A G540 with motors and PS as a package is north of $500 which is the next best package deal. You can get it with wiring for about $75 more.

I looked at ala-carte pricing of similar components but couldn't match the price of the Chinese package.

Ther is some risk that the TB6560 based driver board is a piece of crap, but if thats true, I'm only out the board, not the drives. The drives are not described well in the e-bay postings, but I'd guess they are bipolar 4 or 6 wire drives that can be configured either bipolar or unipolar and the TB6560 board supports both so you can get some variation of speed or torque.

Help me spend some money guys and gals!

[doorknob]

I bought a similar setup to the one that you are considering. I've been busy with other projects, and so I have not yet completely set it up, so I can't give you a final verdict.

I got three 290 oz.-in. 6-wire motors from Longs Motor, part number 23HS8610.

The motors are rated at 1.0 amp per phase. One thing that I did not realize until after I bought them was that the inductance of each winding is rated at 18 mH, which is very high. If you follow the formula for determining the voltage to use based on the winding inductance, you end up with a much higher desired voltage than what can be handled by the TB6560 board. I expect that they will work OK, but the maximum speed may be a concern.

I have a 3-axis TB6560 board and a 24-volt switching power supply, which I have mounted in a suitable enclosure. I have researched a lot of info about peoples' successes and failures with that board, and I am prepared to deal with any possible problems that I may encounter, because at the moment I need to keep to a budget.

One note to keep in mind - the TB6560 board is designed to drive 4-wire bipolar motors (it can drive typical 6-wire motors wired as 4-wire motors, which is what I plan to try). The TB6560 board will not drive 6-wire motors in unipolar mode.

Bearing in mind the fact that I have not yet hooked things up, my recommendation would be that if you want to try the TB6560 board, make sure that the motors that you get have a suitably low winding inductance - that way, if you later decide to go with a different driver board such as the G540, your motors will be well matched to its capabilities. For comparison purposes, the Keling motors with a similar torque rating have a winding inductance of about 2.2 mH, and they also have a higher current rating than the motors that I bought (approx. 2 amps, or 4 amps, depending on how you wire them). My guess is that driving more current through the windings should produce more dynamic torque, even if the rated holding torque appears to be the same as the lower-current motors.

After I bought my motors, I decided that I would prefer dual-shaft motors to the single-shaft motors that I got (because I want to do some experiments with placing encoders on the motor shafts, and I may want to also place handwheels on the shafts in order to retain some manual operation capabilities, but most people seem to go with single-shaft motors). Keling sells both single- and dual-shaft motors. I have several CNC projects that I am working on, and I plan to get some motors from Keling for those other projects.

Also make sure that the TB6560 board that you get has a current rating to match the motors that you get. The board that I got was rated for driving 1.0 amp motors, which is the proper rating for my motors, but they also have a version of the board that is rated for 3.0 amps. That rating is set by the value of a resistor on the board (one resistor per axis, that is) in conjunction with a DIP switch setting, and so if necessary you could always modify that after the fact.

Hope that helps...

[ldanut]

who knows anything about this :

3-Axis CNC Stepper Motor Driver Board Router Mill | eBay

[Michael In Cali]

who knows anything about this :

3-Axis CNC Stepper Motor Driver Board Router Mill | eBay

Search this message board for "easy-cnc".

I like the concept of socketed components, but apparently tech support and board reliability are poor.

[cgodwin]

I'm considering a kit from Keling - 3 x 425 oz-in steppers, 3 bipolar drivers in a nice metal box, a breakout board, and a 36V-9.7A switcher. At $399 it is a little more money than the Xylotex, but the modular approach means less to replace if I fry something. I believe all the components are from China, but I feel more comfortable spending a little extra to buy it domestically. A very similar setup with mostly the same components is available from buildyourcnc, but maybe Keling is a more established supplier?

[bjesson]

Randy,

Funny you mentioned forgetting the parallel cable as I did the same thing and had to place a second order for it. From research I have done you need to be careful with the cable - "ordinary" parallel cables used for printer connections won't always work. Something to do with not all pins are wired from one end to the other I think.

Dave

Yep, cheap printer cables only have the required pins connected, better to get the correct cable and even better to just get it from a CNC supplier so you are sure all pins are intact.

billj

[bjesson]

I went with the ebay chinese model all-in-one kit. Came with a variable 24v-9A (roughly, might have been 8.5A) 3x 287oz.in. 3.0A steppers, TB6560 3-axis 3.5A up to 16 mic steps driver board, parallel cable, and a CD with Mach3 and a bunch of manuals. $210 total and 6 days to arrive.

I have plenty pics in these forums to see their performance.

Billj