PK296A2A-SG7.2 is 850.00 in Mike's store, the 4.5 series is 138.00 (ish) online. So, for almost a similar cost you can do either within a few hundred dollars of each other.

Wow -- That is not a current price - Motors are now 260 each plus shipping :)

OK now fixed in the store - Those were a set of NOS motors I had. The motors in the store now are $260 each plus $15.00 shipping.

Hello good friends, someone has reference of this engine and the driver? is to assemble my mechmate.

http://www.circuitspecialists.com/ne...gh450A-08.html
http://www.circuitspecialists.com/st...ler-cw250.html

Hevert,

There's not enough information on those two sites to offer recommendations. The stepper-driver, in particular, is lacking in information. Most common stepper motors move 1.8 degrees per full step (200 steps per revolution). With no gearing and a 1.25-inch spur gear, the resolution would be 0.0196 inches per step. That would never work. Half-step would improve that to 0.0098 inches per step. That is not good enough. Gecko stepper drivers have 2,000 steps per revolution, which would give 0.00196 inches per step (without gearing).

There are so many possibilities and so few resources that, when I get private email asking for my advice on a particular stepper motor or a particular stepper driver, I almost always respond by saying that there are several proven motor/drivers that have been used by many builders. If you pick one of those proven motor/driver sets, you can expect the same results that others have had. If you decide to buy something else, then you'll have to do all of the testing to see if that motor and that driver meets your needs. If you're comfortable experimenting with stepper motors, why not just buy one motor and one driver? Thoroughly test it and if it meets your needs, buy the other motors and drivers.

hi richards, thanks for your reply, you're right, the trouble is that I have little experience with stepper motors, better find something that is already used in this MM, thanks friend

Hevert,

Contact Metalhead (Mike). He sells everything that you'll need to build your MechMate.

Read carefully the "build threads" that describe how others have built the electronics for their machines.

Because I like Oriental Motor stepper motors and Geckodrive stepper drivers, if I were building a minimal machine that did not need a lot of extra inputs and outputs, I would use the Oriental Motor PK296A2A-SG7.2 motors with a G540 stepper controller as the basis for the electronics. I would use a 35VDC to 45VDC power supply. If I needed more inputs and outputs, I would use either the PK296-F4.5A or PK299-F4.5A stepper motors with belt-drives or the PK296A2A-SG7.2 geared motor driven by the G203v stepper driver and a PMDX breakout board. The power supply would be 35VDC to 50VDC depending on the motor.

The most important thing that you should do is to read the posts until you are familiar with how others have built their machines.

Hi Richards, reading some post, I saw that you were talking of Oriental Motor PK296A2A-SG7.2 and transmicion box of 7.2:1. you were saying that it is better to use email gearbox with 4:1 would 1400oz in, but the PK296A2A-SG7.2 is limited by its gearbox and less serious in oz? that's true?

mike, you shop online? link?

Helvert,

The PK296A2A-SG7.2 motor has a 7.2:1 gearbox attached to it. The motors that I've tested had minimal backlash. Some users have reported that the backlash increased with usage and that the increased backlash is too much for accurate results. The gearbox is rated at 40 in*lbs (640 oz*in).

A belt-drive transmission has no backlash if the belt is properly tensioned; it also allows all of the motor's torque to be multiplied by the transmission's ratio. A 4:1 transmission would increase the torque by 4X. A 3:1 transmission would increase the torque by 3X.

I prefer the belt-drive transmission; however, it is more expensive to build and it is bulkier than the PK296A2A-SG7.2 motor/gearbox.

Send metalhead (Mike) a private email to get information about the products that he sells. I think that you have him confused with me. I highly recommend that you buy whatever you need from him. He has had me test some components for him, so I know that he has done his best to find high quality parts for your MechMate, and then had those parts tested to verify that they worked as advertised.

Here is my link

http://www.cvsupply.com/servlet/the-MechMate/Categories

Are these any good?
 

I am about ready to start assembling my electronic components for my build. I no very little about the overall dynamics of this part of the build.

I have the mechanical aptitude do do any of the construction and fitment to complete this project, my hold up is the electrical side.

I have been reading and watching so much stuff about the electrical that I am COMPLETELY lost. I want as much as is possible to just buy the components, run the wiring per instructions, and get this going.

As I have been languishing on the side lines for several years now, it looks like this winter I will have time to get my build in gear.
So, I was looking on line for DEALS? [are there any really}, and I located a number of companys that are offering complete component set ups on eBay for what seem like very reasonable prices.

Here is one I would appreciate an evaluation on from the great electronic minds we have on this board.

http://www.ebay.com/itm/free-shippin...item4166c5f264

I am planning right now to go direct drive [NO GEAR BOX, no belt drives].

Is this a proper approach?
And would this set up or a similar one work? I am planning a 4'x8' work area on the MM, with about a 8" Z- travel.

Those kits deliver extremely poor performance. I've seen someone using a similar kit to that on a non mechmate homebuilt machine. He ended up switching to Gecko drives and 400oz motors (4x smaller) and got about 5x better performance.
Whenever I see someone trying to save money on motors and drives, they almost always end up replacing them, which costs nearly twice as much in the long run. I'd stick to what's been proven to work well over the years. The slightly higher initial costs are well worth it.

What would you attribute the poor preformance too?

Are the motors [according to their quoted specs] not up to the job? Or is it something else in the equation that wold be an issue?

Is my idea of going direct drive a possible problem as regards finish milling quality?

PS Thank you for your reply

Bob,
The answer to your question is very involved.
The VERY quick response based on the cost/value of that package - around 630.00 is that it might not be that good of a deal.
The very large Nema 34 like you have found, have challenges with performance.

Direct drive is not an issue - the original MM and many others are using Direct drive. The issue with any direct drive system is resolution. With the addition of a belt drive transmission 3:1, 4:1 or a 3.6 or 7.2 gearbox, you gain resolution and still maintain usable speeds. The belt drives or direct drive have limited back lash which is a plus for some CNC applications.

IF I was to go direct drive, I would use the G540 gecko all-in-one controller and either a Gecko stepper or one from http://www.kelinginc.net/NEMA34Motor.html

With any of those choices, you must pay keen attention to the inductance (mH) matching of the drive to the motor. Refer to the Mariss formula at the Gecko website or the sticky thread on the forum *how to choose your motors* for detailed math explanations.
The G540 includes the Computer breakout board in the cost of the G540. You could use that savings to buy the transmission plates or more expensive, correctly matched motors and have the best of both worlds.

Good luck with your choices.

Sean

This is not a place to cut corners really. You read over and over folks having to re-buy drive systems. Look at proven systems. The 640oz direct drive motors, PMDX-126 and Geckodrive systems will give you a platform that will perform direct drive as well as position you to go to belt drive when/if you ever want to. It will also give you a system that many (not just here) can support. Oh - don't cut corners on wire quality either.

I second Sean's advice, with the caveat that at the moment, Gecko doesn't have any NEMA34 motors that match well with the G540, and Keling has a perfect match (look for the one that says it) at $70. 4 x $70 + $300 = $580, which is pretty tough to beat. I'd add the transmissions.

Brad,
Thanks for the followup. I actually have ordered those Keling's for my next machine. I have the g540 and will use the 3:1 belt drive. Mixing it up this time around!