help getting 1000mm/s setup

Bearings/Motors/Belts/Gears/Etc.

help getting 1000mm/s setup

Postby georgehine » Thu Aug 30, 2012 2:43 am

I have a chinese laser I am wanting to make engrave at 1000mm/s it currently tops out at 500mm/s
what would I have to do to make it hit 1000mm/s
it currently has a .9 step .96 amp 36W motor and the stepper drive set at .75A though it is capable of 2.0 amps
I set the drive to 1.0 A and was able to get a nice 625mm/s but in fear of burning up the motor I set it back to .75A
thanks in advance!
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Re: help getting 1000mm/s setup

Postby macona » Thu Aug 30, 2012 7:23 am

You need more voltage to go faster, not more current.

Most motor insulation can take up to about 90c.
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Re: help getting 1000mm/s setup

Postby georgehine » Thu Aug 30, 2012 3:35 pm

It currently has a 24v power supply.
the stepper drive is rated for 14v - 40v and recommended is 24v - 36v
I will get a 36v power supply and try! thanks for the help. I will post here with my results, once I have done this.
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Re: help getting 1000mm/s setup

Postby Techgraphix » Thu Aug 30, 2012 9:06 pm

Hi, a few thing that will increase the speed:
Lower the selfinduction of your steppermotors :? : If you have steppermotors with 8 leads, you can place the coils in series or Parallel. When you place them in series, the selfinductance will be doubled... when you place them parallel you will half the selfinductance... What does this mean and what are the pro's and contra's..
Selfinductance will create a voltage while rotating.. The faster you go the higher the voltage.. If you supply only 24V and the inducted voltage is 20V there will only be 4V left to let a current flow.. Current is torque.. You want a higher torque at higher RPM's so you have to increase the supply-voltage and decrease the selfinductance.
A contra of parallel is that you need twice the current.. your supply must be able to deliver that.
Use better cables.. A lot of energy is lost in cheap, thin cables and connectors. Keep your wires as short as possible and use appropriate cables.
Think of buying good stepperdrivers. Leadshine's or clones or Gecko's make a lot of difference in speed over most of the lowcost driver-IC's When you buy them, take as high working voltage as you want to pay.. also replace the powersupply.. (maybe you need to buy a small separate supply for the controller..)

You can increase the current as long as you can hold the steppermotors for a few seconds (ie not hotter than 60 degrees C) after a quarter of an hour moving.. Many stepperdrivers reduce the current to 50% after 1 sec standstill

Ofcourse your steppers must be powerfull enough and friction must be low..

Kees
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Re: help getting 1000mm/s setup

Postby lasersafe1 » Thu Dec 06, 2012 10:03 pm

I played all these games when rebuilding my ULS25. Voltage is the only way to get there. I use stepper drivers from Oregon Micro-Systems that can take 80V. I feed them 60V from a simple transformer that has a full bridge rectifier and a large cap. The OMS drivers also have the current reduction feature that drops the current a few moments after all stepping is done. I actually programmed this "energy saving" feature to have a very low holding current so if I want to reach up and move the X or Y by hand, it is easy, but when I'm running a job these little NEMA 17 motors can fly at 1000 mm/sec. Even after long runs, they are only warm to the touch.
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