X3 Conversion Start

[HackMax]

Hi. I'm a newbe here but I've been lurking for quite a while. I've been deciding a long time on buying a mill to make aluminum parts with and have finally made up my mind to do it. In all the information I have gathered from this wonderful web site and by surfing the web I feel that the X3 Grizzly model will be the best mill I can afford at this time. I want to convert this mill as cheaply as I can at the start and then keep upgrading and adding on it over time. But now I have some questions on some of the parts I have decided to start with.

First – I am getting my electrics from http://www.kelinginc.net as they seem to be the most reasonably priced place so far. I'm a little confused on the stepper motors though. I'm looking at the torque-speed curve of the NEMA 23 BIPOLAR STEPPER MOTOR 425 and the NEMA 23 BIPOLAR STEPPER MOTOR 282. The 425 starts out high but rapidly falls as speed increases whereas the 282 has a better curve by the looks of it. Of course the torque starts out lower but at 2000 pps the smaller of the two has more torque. Then at 3000 it looks really sad for the big motor. First of all is 2000 pps an average speed I would be looking to machine 6061 aluminum on the typical X3 conversion? I would probably be looking to hook the motors up directly. Does anyone know where the most common speed falls? I need to get this machine to be as productive as I can and need the best speed at making the part as possible.

Also I need to order the aluminum for the motor mounts does anyone have the size of the stock I should be getting? I also need couplings to connect to the acme rods and would like to know the sizes that I need to look for. I have no way to turn the ball screw rods to the proper dimensions as yet but I plan to add a small lathe to my arsenal later.

Thanks for your help.

[SpeedsCustom]

Well the higher the torque the stepper has, the more speed it loses. Meaning, depending on how high you want too run your motor speed will depend on how high the rated torque is and in what way you wire it/amperage.


Typically, a motor with high torque will not have an advantage over speed compared too a lower torqued motor.



I'm looking too get rid of my c11 BOB, if your interested, I would really like too sell it. I can't seem too get any buyers!


-Jason

[alexccmeister]

If you want to turn a ballscrew. My suggestion is get a reasonably sized lathe. A 9 x ?? would be a good start. I personally have a C3 which is the same as a 7x14 but I am not sure if that will cut a ball screw as well as a 9 or 10" lathe. The large lathe will have better turning capability.

As for the X3 conversion, there are a few thread dedicated to that. I am sure you can get a lot of info from there. I think one of the thread the OP may have posted some autocad drawings of the parts as well. Not sure though, you will have to do some searches on that.

Just my 2 cents. Good luck

[HackMax]

Originally Posted by SpeedsCustom Well the higher the torque the stepper has, the more speed it loses. Meaning, depending on how high you want too run your motor speed will depend on how high the rated torque is and in what way you wire it/amperage. Typically, a motor with high torque will not have an advantage over speed compared too a lower torqued motor. I'm looking too get rid of my c11 BOB, if your interested, I would really like too sell it. I can't seem too get any buyers! -Jason

Thanks for the info - I kinda gathered this from other threads. I was looking for someone that was familiar with this mill and their experience with it as far as milling speed of aluminum without skipping steps or bogging down the mill.

Maybe I can make myself more clear by giving more info. Say... milling a slot in a piece 6061 stock with 1/4" endmill say at 10 ipm at a depth of .2 in. what would be the motor speed (pps) of this operation on their mill. It's probably a tough question to answer really because I don't know how you would get this information. It looks like I'll just give the 282s a shot. If they can't handle it I'll have to work on getting some ballscrews and find a lathe.

As far as the BOB I'm hoping I won't need to use that from the start. Just a simple C10 for now. This is a real budget conversion at the start but as time goes on I will add more. I really want to see how cheaply it can be done and at what results. I will post the info in this thread for others that are budget minded.

[Crevice Reamer]

You need to understand: Pulse Per Second is different from RPM or IPM.

Each pulse will move the motor one step. At FULL step, (200 per revolution) and with 5 TPI ball screws, It will take 1000 pulses to move the table one inch, and 10,000 pulses to move the table 10 inches. To move the table ten inches in one MINUTE will require 10,000/60 or approximately 167 pulses per second.

2000 pulses per second would equal 120 IPM table movement.

Bear in mind that to get maximum speed, your motors need to be wired in bipolar parallel and powered with best power supply voltage. Formula for best power supply voltage = 32 times the square root of motor inductance.

CR.

[HackMax]

Originally Posted by alexccmeister If you want to turn a ballscrew. My suggestion is get a reasonably sized lathe. A 9 x ?? would be a good start. I personally have a C3 which is the same as a 7x14 but I am not sure if that will cut a ball screw as well as a 9 or 10" lathe. The large lathe will have better turning capability. As for the X3 conversion, there are a few thread dedicated to that. I am sure you can get a lot of info from there. I think one of the thread the OP may have posted some autocad drawings of the parts as well. Not sure though, you will have to do some searches on that. Just my 2 cents. Good luck

Thanks for the info I did find one thread in particular by cadmonkey that helps me with the amount of stock I need for the motor mounts. He has done a super job on his mill. He is one bright dude. I'll no doubt use most if not all his drawings for reference for future upgrades but right now budget is on my agenda and he used Gecko drives and ball screws in his build. I really want to see how cheap I can get away with to start out. I noticed HF has a 15% off sale now but I don't know if that will apply to special order items. If so I will get their X3 and save a few hundred.

Lathe is in my plans for my future shop but right now I need to keep a strict budget. Cadmonkey also got a lathe to do his ballscrews but he used the 7 in. model. I will probably get the one you suggested when the time is here but for now I have a friend that has access to a lathe that I can use.

Rick

[Crevice Reamer]

If lowest cost is your goal, then you should forego buying a lathe and pay somebody like Hoss his reasonable fee to cut your ball screws.

The new G540 is the most bang for the buck in drivers/BO Board. It will probably work best with the 282 oz motors.

The X3 Z axis normally uses a N34 motor however. NO one has yet found a N34 motor that the G540 can run well.

If you really want best speed, then you may have to go to a full sized Gecko driver like the G201 or G203V to get the 6A that most N34 motors require.

CR.

[HackMax]

Originally Posted by Crevice Reamer You need to understand: Pulse Per Second is different from RPM or IPM. Each pulse will move the motor one step. At FULL step, (200 per revolution) and with 5 TPI ball screws, It will take 1000 pulses to move the table one inch, and 10,000 pulses to move the table 10 inches. To move the table ten inches in one MINUTE will require 10,000/60 or approximately 167 pulses per second. 2000 pulses per second would equal 120 IPM table movement. Bear in mind that to get maximum speed, your motors need to be wired in bipolar parallel and powered with best power supply voltage. Formula for best power supply voltage = 32 times the square root of motor inductance. CR.

Super information!! Thank you! That was the information I was looking for. 120 IPM is way out there so maybe I should get the 425s since I will be starting out with the acme screws that came with the mill. Now I have some idea on how to figure out what I need to get.

Rick

[Crevice Reamer]

The standard screws are approximately 10 TPI. (At least the ones on my Grizzly SX3 were) So 2000 PPS will get you 60 IPM.

Properly powered, the 425s are plenty fast. I have 5 TPI ball screws.

I am powering 72 volts to the 425s on my X and Y and the 1200 N34 on Z. Rapids on X and Y are 250 IPM. On Z, with the heavy head until I make a balancer, I only get 115 IPM rapids.

Rapids are not important until you need speed for a tool changer rack at the end of the table. THEN they speed up or slow down the whole job.

CR.

[cadmonkey]

I would definitely get the 425s if you are mating up to the existing ACME screws - those things are definitely not efficient.

Thanks for the compliments - goodluck on your conversion.

[Crevice Reamer]

BTW, HackMax: Welcome to the Zone!

CR.

[HackMax]

I plan on getting the Keling KL-6050 drivers with the 425s (now) for the x/y and a NEMA 34 640 oz. for the Z. I was planning on building a linear 40v power supply but maybe I need to go a little more. Rapids are of little concern right now, as you mentioned, I just need to push the tool though the metal at a decent speed without losing steps. Thanks

Rick