[Claude Boudreau]

I`m trying to speed up my home made cnc router by swapping my 1605 ballscrew to 1610.
My maximum speed right now is about 50 in/min, anything faster will make my stepper loose steps.(V-carving hardwood)
Can I expect to double up my speed?

[Fastest1]

Have you experimented with different accel rates?

[Fastest1]

Let me elaborate a little more. I too am running 1605's on my x & y on a mill. During testing for lost steps etc. I was able to achieve a max speed in Y of 331ipm. This was with a step per unit in the area of 8000 (200 x 5 x 8) as I am running a 1/8th microstepping with a kernel speed of 25k in Mach IIRC. I have my accel on 80 in real use but it was repeating at 331.

[BAMCNC.COM]

Depends on when you loose steps, before max speed, or at/during max speed. You can see/hear when it is if your losing steps badly. Acceleration will be just that, accelerating to top speed (velocity). Which ever your losing steps at simply turn down, also make sure your step and dir pulses are long enough (5's) if using mach. I bet you can go a lot faster than you are, your just trying to get there to fast (acceleration)

[ger21]

Can I expect to double up my speed?

What motors, drives, and power supply voltage are you using?

[Claude Boudreau]

What motors, drives, and power supply voltage are you using?

xylotec 425 oz in motors
xylotec 24 volts power supply 5amps
mechatronic 3 axis drive
mach 3 controller

I'm hesitant going with less inductance motors wondering if they will have enough torque to do the work

[Claude Boudreau]

Depends on when you loose steps, before max speed, or at/during max speed. You can see/hear when it is if your losing steps badly. Acceleration will be just that, accelerating to top speed (velocity). Which ever your losing steps at simply turn down, also make sure your step and dir pulses are long enough (5's) if using mach. I bet you can go a lot faster than you are, your just trying to get there to fast (acceleration)

when joging at full speed if I squeeze my motor coupling a bit simulating a working force I was able to hear some missed steps so I lower my speed to 45 and it help

[ger21]

I wouldn't count on doubling your speed with those motors and that combination.

As a guess, you might see the same improvement using smaller (low inductance) motors as you would changing the screws.

How much will it cost to switch screws? And how long are the screws? A G540 package with 381 oz motors and 48V might be a better option, if the price of the screws is high. You could also try selling your motors on Ebay to par for the upgrade.

[harryn]

You could try dropping down to 1/2 steps or even full steps rather than 1/8th steps and see if that helps any.

You could also add a pulley for a 4-5 x up ratio (even temporarily) to see if that helps.

I agree with Gerry though, it is a lot easier to try changing one motor on one axis to the gecko setup and a higher voltage PS and see if it solves your problem rather than the cost of changing lead screws.

5 amps is not much, do you see any evidence that you are running out of power from the supply when all 3 axis are running ?

[Claude Boudreau]

I wouldn't count on doubling your speed with those motors and that combination.

As a guess, you might see the same improvement using smaller (low inductance) motors as you would changing the screws.

How much will it cost to switch screws? And how long are the screws? A G540 package with 381 oz motors and 48V might be a better option, if the price of the screws is high. You could also try selling your motors on Ebay to par for the upgrade.

My cutting area is 19x39 inch right now.
Ive just bought 1610 ballscrews with nuts (1500mm and 1600mm (C7) to increase my cutting area to 48x48) for about $400 for both, on ebay, with end supports and machined end.

[BAMCNC.COM]

Will your driver support a higher voltage?

[109jb]

As for lower inductance motors, if you have 2 motors with the same holding torque and one has lower inductance, the one with lower inductance will generally maintain torque to a higher speed than the one with higher inductance. Also, the lower inductance motor will require a lower power supply voltage. I would not count out the possibility of using lower inductance motors.

[ger21]

If you already purchased the screws, then yes, you should definitely get quite a bit more speed.
Do not change to 1/2 step mode. If you have dual shaft steppers, then adding dampers might also give you a big boost in speed. As a quick test, drill a hole in a hockey puck (tight fit, maybe 6mm?) and slide it on the back shaft. Dampers tend to give big performance gains on Xylotex drives.

[harryn]

Running in full step or 1/2 step will give more torque at a given speed than the current 1/8th step mode.

It is a useful "test" to see if the issue is motor torque related. I agree it is not ideal to operate in this mode, but as a test - possibly.

Once you determine if it is a torque related challenge, then you can think about what driver / motor changes can help solve this.

[Claude Boudreau]

Will your driver support a higher voltage?

that mechatronic driver spec recommend 24v 7a
Max 32v

[Claude Boudreau]

If you already purchased the screws, then yes, you should definitely get quite a bit more speed.
Do not change to 1/2 step mode. If you have dual shaft steppers, then adding dampers might also give you a big boost in speed. As a quick test, drill a hole in a hockey puck (tight fit, maybe 6mm?) and slide it on the back shaft. Dampers tend to give big performance gains on Xylotex drives.

Thanks for the inputs, seen some videos about dampers,
never tried them though...

In theory I should double my speed,at a same rpm.
what will happen to my working force(half?)

[ger21]

In theory I should double my speed,at a same rpm.
what will happen to my working force(half?)

At the same rpm, you'd have the same torque, but you'd have less force, due to the higher lead screw having a lesser mechanical advantage. If you have less force, then you probably won't be able to go twice as fast.
It's very complicated to try to determine what the velocity will be.

[xaruum]

You are fighting the limits of the xylotex/psu. If you need to maintain the 1/8 microstepping then dampers are your best bet. Other wise jump up to 1/4 step or 1/2 step ( a simple jumper change - and mach change too ).

The real issue as far as speed is the size of those steppers. They -really- aren't going to work well at the 24v/2.5a that the xylotex can push. Smaller steppers or a controller capable of handling at least 48v/12a is going to give you the best results.

[Claude Boudreau]

As for lower inductance motors, if you have 2 motors with the same holding torque and one has lower inductance, the one with lower inductance will generally maintain torque to a higher speed than the one with higher inductance. Also, the lower inductance motor will require a lower power supply voltage. I would not count out the possibility of using lower inductance motors.

Everythings else staying the same , it was my presumption that a lower inductance motor would give me less working force...?

[ger21]

Everything else staying the same , it was my presumption that a lower inductance motor would give me less working force...?

IF the two motors have the same rated holding torque, the one with lower inductance will give you more torque (and force) the faster it spins.

However, you can't just change the inductance and keep everything else the same. A lower inductance motor will typically have a higher current rating (and lower voltage rating).