Author Topic: Air assist connected to motor pins  (Read 835 times)

chieflbm

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Air assist connected to motor pins
« on: November 28, 2017, 10:31:40 AM »
Is there some other setting to make the motor pins turn on the fan when the laser is on?

I have the fan (https://www.amazon.com/gp/product/B00MJU6JR2/ref=oh_aui_detailpage_o01_s01?ie=UTF8&psc=1) connected, but it never comes on?

Any ideas?

Thanks


ggallant571

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Re: Air assist connected to motor pins
« Reply #1 on: November 28, 2017, 10:36:26 AM »
How is it wired? The fan is 12V 0.15A.
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Zax

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Re: Air assist connected to motor pins
« Reply #2 on: November 28, 2017, 10:39:20 AM »
The motor output should work, it's 12V and switched with the laser. The problem may be you aren't using full power, so the fan would be getting a PWM input and may not start.

chieflbm

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Re: Air assist connected to motor pins
« Reply #3 on: November 28, 2017, 11:01:48 AM »
Ah thanks Zax, yes I have only been doing 50% power test burns.

The fan is connected directly to the motor pins on the controller board. This diagram has the motor connector shown in green text (https://ae01.alicdn.com/kf/HTB1YdzFPFXXXXbqXXXXq6xXFXXXT/222019976/HTB1YdzFPFXXXXbqXXXXq6xXFXXXT.jpg)

Is there another way to make the fan come on all the time, when the laser is on, even at lower powers?

I have a home brewed ventilation pulling smoke out of my enclosure, so I can see it moving away from the laser target area, but the air assist may help even more.

Thanks for your replies !!

Zax

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Re: Air assist connected to motor pins
« Reply #4 on: November 28, 2017, 03:52:28 PM »
Not unless you do something custom. The problem is that both the laser (S-pin) and MOSFET are switched from the same D11 pin, you would need to have a laser enable pin set in the firmware, say D12 and use that to switch a relay for the fan.

chieflbm

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Re: Air assist connected to motor pins
« Reply #5 on: November 29, 2017, 09:48:00 AM »
Another question along the same lines, if the fan will spin up at power 100% -- I'll try that tonight.

Is it better to :

    (1) run the power at 100% or close to it and increase/decrease the speed to adjust burn levels   -or -
    (2) vary the power and speed together

My first try at getting very light lines was more what I would consider a medium range burn, not black, but a lighter brown. I could never quite get a very light line.

Zax

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Re: Air assist connected to motor pins
« Reply #6 on: November 29, 2017, 10:07:37 AM »
I always start at 100% power and use feed rate to get the correct burn, that way I know it's the fastest possible.

If feed rate gets about 3000 I begin lowering the power as I don't want to cause backlash (stretching of the belts) or possible lost steps (steppers have poor torque at higher rates, especially with micro-stepping).

ggallant571

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Re: Air assist connected to motor pins
« Reply #7 on: November 29, 2017, 12:17:39 PM »
It also depends on the medium you are burning. I do mostly slate and mirrors and rarely get the speed past 1200mm/min. On one laser I have acceleration completely removed from the firmware and on the other it is set very high. With slate the laser creates mini explosions (my explanation) and very fine detail is not possible. With mirrors I expect the burn to be accurate to 0.1mm.
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