New Machine Build- 24v vs. 36v for X2.

[spaceballs_3000]

Hi,

Ordered X2, X2 CNC Fusion kit, and Keling X2 sig kit motors\drivers.. etc..

I accidentally ordered the 24v power supply vs the 36v one (with KL23h286-20-8b 425oz-in), will 24v work for my light metal work needs? anodized aluminum. through later I like to work on small bocks of Al or harder metal.

Also has anyone got any tips of any bumps I might run into during the conversion? so I'm not completely surprised when I run into them.

[Crevice Reamer]

Originally Posted by spaceballs_3000 Hi, Ordered X2, X2 CNC Fusion kit, and Keling X2 sig kit motorsdrivers.. etc.. I accidentally ordered the 24v power supply vs the 36v one (with KL23h286-20-8b 425oz-in), will 24v work for my light metal work needs? anodized aluminum. through later I like to work on small bocks of Al or harder metal. Also has anyone got any tips of any bumps I might run into during the conversion? so I'm not completely surprised when I run into them.

You did not say what drives you ordered. The 425 oz MOTORS will run at up to 80 volts. The drives may run at up to 50 volts or more.

The voltage will not affect your cutting speed. That will be a fairly low speed in an x2. It's moving the axis in AIR (or rapids) where the voltage is important. Time is money. Time wasted waiting for a slow positioning rapid means lower job productivity and money wasted.

Stepper motors are not run by continuous current, but by pulses of current. A low voltage pulse takes longer to charge the motor coils than a higher voltage. So the motor will move less quickly with a low voltage pulse than a higher one.

You may not be satisfied with the speed of the 24 volt system. The 36 V PS will be faster--The 48 volt PS (If ok with drivers) might be a lot better.

CR.

[spaceballs_3000]

Thanks for replying and all the infomation.

Drivers I got are http://www.kelinginc.net/KL-4030.pdf so to up 40v.

I'll see if I can upgrade to the 36v one instead of the 24v.

Also I'm confused, the drivers I on the website say 125 microstep resolution --> http://www.kelinginc.net/Three23XCNCPackage.html but the ones I got say 1/64 microstep. is the web site wrong?

How about heat issue?

[Crevice Reamer]

Originally Posted by spaceballs_3000 I'll see if I can upgrade to the 36v one instead of the 24v.

Better email right away (Include order date)--And CALL first thing (Central time) Monday Morning. Keling ships at WARP speed.

CR.

[Crevice Reamer]

Also, three 2.8A motors are just above the envelope of the 5A PS. If you ever imagine going to 4th axis, you might want to spend the $10 for the 36V 8.8A PS.

CR.

[Crevice Reamer]

If you haven't already got it--You might want to get the X2 belt drive conversion from Little Machine Shop--$119 and worth every penny!

http://littlemachineshop.com/product...2560&category=

CR.

[Crevice Reamer]

Originally Posted by spaceballs_3000 Also I'm confused, the drivers I on the website say 125 microstep resolution --> http://www.kelinginc.net/Three23XCNCPackage.html but the ones I got say 1/64 microstep. is the web site wrong?

Nope!

From the Keling website:

2: KL- 4030 Microstepping Driver, Heat Sink is included, $54.95/pcs Specification Features of this driver * Voltage up to 24 to 40VDC, current output up to 3.0 A * Selectable resolutions, 1,1/2, 1/4, 1/8, 1/16, 1/32, 1/64 * Suitable for 4,6,8 lead motors * DIP switch current setting with different values * Over voltage, heat and short-circuit protection Automatic Idle-Current Reduction One Year Warrenty

The FULL STEP of your motor is 1.8 degree or 200 steps per revolution. That is set in concrete and will never change. Micro steps however are arbitrary almost "imaginary" electronic simulations. Some say any microsteps above ten is superfluous. Even if you COULD get 125 microsteps, that doesn't mean you will get that high of a resolution.

Anyway, the higher you set your micro steps, the more pulses it will take per revolution and the slower your rapids will be.

For example, if you are using 5 TPI ballscrews, your motor will turn 5 revs per inch of travel. At FULL step, that will be 5 x 200 or 1000 steps per inch--Or a resolution of .001, and 1000 pulses to get it there.

If you are using the stock X2 16 TPI (20 TPI if it's a Micro Mark) Acme screws, then your motor will turn 16 revs per inch of travel. Full step = 16 x 200 or 3200 steps per inch, or a resolution of .00031, and 3200 pulses to get it there.

That's using FULL steps. As you increase micro steps, the above gets larger. Bear in mind that there is a finite limit of pulses that (depending on how fast your computer is) Mach 3 can produce. To be conservative, let's say it's 35000. You will run out of pulses long before you reach maximum microsteps.

A stepper motor loses torque as it increases in RPM. At lower voltages, it isn't likely to attain more than 500 rpm before stalling or skipping steps. With stock screws and full step, 500 rpm would equal about 1,600,000 pulses. That's not going to happen, You may only get 11 inch per minute rapids, although a step-multiplying drive might help.

CR.

[spaceballs_3000]

Wow thanks for the detailed information!

I've emailed them already, I'll call Keling tomorrow, and ask for the 36V 8.8A PS instead.

Interesting about micostepping. I want the smallest steps possible, which caused me some concerned as I ordered ballscrews to replace the Acme screws. But since the ballscrews has lower revs per inch I fear I'll be loosing accuracy. But also I read that the ballscrews remove the much backlash as seen from the Acme screws. So are you saying that in the end microstepping (anything past 10) will not help improve my resolution then?

Reason I want high accuracy is later on I'll also be mounting an 50 watt laser on the side to do laser engraving also, and it has Very small pinpoint spot so if my steps are too big I'll have engravings that will have an horizontal or vertical line (kinda like windows blinds) in them.

I'm not too much in hurry for rapids (for now), as my faceplate's that I need only have a few holes in them.

"X2 belt drive conversion" Thanks! I've read many good things about them... Going to place an order....DOH it's backordered.. hum... guess I'll have to wait.

[Crevice Reamer]

The original source:

Belt drive kit replaces the factory drive gears and provides a quiet running and less fragile spindle for your mini-mill. It takes only 15 to 20 minutes for the bolt on installation of the kit on a mini-mill and requires no drilling or cutting modifications to the mill. The kit includes all needed hardware for the installation. The kit expands the speed ranges of the mini-mill from 0 to 1100 RPM in low range to 0 to 1700 RPM, and changes the high range's speed from 0 to 2500 up to 0 to 4300 RPM. This will allow most drilling, milling and boring to be performed in the low range. The new high range will allow milling with very small diameter end mills, burrs or engraving tool bits. Belt drive kits are $119.95 plus shipping.

http://stores.stirlingsteele.com/cataloglist.html

CR.

[Stepper Monkey]

You really don't want the smallest steps possible. You don't need them, either, but you REALLY don't want them.

Unless you have very specialized and expensive steppers, anything over 1/8 to 1/10 per step is wasted. The motors just won't resolve that accurately. Even at 1/8 step they are still going to show at least 5-10% or more non-repeating error per microstep. Go to 1/64 and the error margin is actually larger than the step increment. It does little good to have a step of 20 millionths, even less to have a step of 20 millionths with a +/- 40 millionths of error. There are specially designed steppers purpose built to do those resolutions for medical and lab chemical metering applications and the like, but they are engineered in such a way as to be entirely unsuitable for milling machines.

Most importantly, think about this; There are only so many pulses Mach can send out per second. If you set the resolution eight times higher using 1/64 instead of 1/8 microstep, not only is there NO benefit at all, you just cut your max speed to one-eighth what it was, as you need eight times as many steps to go the same distance. Once you set the step higher than the resolution of the motors, you are just doing nothing but adding extra work for Mach and severely limiting your speeds - entirely unnecessarily.

[spaceballs_3000]

Thanks Stepper Monkey,

So microstepping isn't going to give me much (if any more resolution), which is what I want to use with my laser.

Should I just stick with the sock Acme leadscrews? 16 tpi, or upgrade to 20 tpi from --> http://littlemachineshop.com/product...gory=879658189

or just use the Ballscrews that I orderd from cnc fusion? --> http://www.nookindustries.com/pdf/Nook_102.pdf

[Stepper Monkey]

16 tpi, 1.8 degree full steps (200 steps/rev), and 1/8 microstepping gives you this:

16*200*8 = 25600 pulses per inch

This means resolution of each pulse (or microstep) is .000039

.000039 - thirty-nine millionths of an inch.

Round this up to, say, 4 hundred thou or so. Or to look at it another way, it takes three steps to go a little over one ten thousandth of an inch.

That is at 1/8 microstep. You can use the same formula to work any other combo. It's TPI x STEPS/REV x MICROSTEPPING = RESOLUTION

At that resolution I just don't think you are going to see any aliasing, which is what the blocky stepped lines you referred to is called. Your machine will naturally have far, far less actual accuracy - but it is a true indication of actual resolution, which is what is important in killing aliasing.