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Engraving / Re: Laser pulse and trace image
« on: December 29, 2020, 10:19:33 AM »
What software do you use to control the laser?
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General Discussion / GRBL problem
« on: December 08, 2020, 07:38:51 PM »
I have grbl-1.1f installed on a couple of machines and today isolated a problem with the firmware. If a limit switch is asserted when the CPU comes out of reset, the HOME function does not work. I ended up manually moving the rail and resetting the CPU.
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General Discussion / Etching ceramic tile
« on: November 30, 2020, 04:43:39 PM »
I've been have pretty good results etching white ceramic tile by painting with black or dark green high temperature paint. When it works, the ceramic surface is slightly fractured and the paint gets firmly embedded. Scratch resistant, dishwasher safe.
The downside is thin lines etched in parallel to the burn path are nice while those perpendicular are not so nice. Especially under a microscope. If the lines are 3 or more pixels wide there is no problem.
Getting the speed/power recipe correct is critical. Being off by 50mm/min can make a huge difference. Tried slowing the speed for single width pixels but it wasn't very helpful (works nice on wood). Wondering if a 45 degree burn would be better.
The downside is thin lines etched in parallel to the burn path are nice while those perpendicular are not so nice. Especially under a microscope. If the lines are 3 or more pixels wide there is no problem.
Getting the speed/power recipe correct is critical. Being off by 50mm/min can make a huge difference. Tried slowing the speed for single width pixels but it wasn't very helpful (works nice on wood). Wondering if a 45 degree burn would be better.
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Trouble Shooting / Re: X Axis Issue
« on: November 04, 2020, 05:56:06 PM »
If I recall correctly, most stepper motors can tolerate 80C.
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Trouble Shooting / Re: X Axis Issue
« on: November 04, 2020, 10:43:12 AM »
I would expect the Y stepper to be set at approx twice the X.
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Trouble Shooting / Re: X Axis Issue
« on: November 04, 2020, 10:03:14 AM »
Which axis has the dual motors?
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Trouble Shooting / Re: X Axis Issue
« on: November 03, 2020, 05:23:30 PM »
Small screwdriver. Slight twist and measure. Some people attach a spring clip to the screwdriver blade so they can measure while turning.
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Trouble Shooting / Re: X Axis Issue
« on: November 03, 2020, 04:59:25 AM »
The driver boards (usually 20-pin) have a user adjustable pot that limits the current to the motor(s). They have a formula that converts the voltage reading to max current. Too little current and the motor can stall, too much and it can overheat. You typically measure the voltage from the screw on the trim pot to GND. If I recall correctly A4998 drivers want something in the range of 0.4V to 0.5V per motor. A fixture with 2 motors on the Y and 1 on the X would require different settings for each driver.
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Trouble Shooting / Re: X Axis Issue
« on: November 02, 2020, 05:42:22 PM »
You could have the current limit set too low. What are your stepper motor drivers? Do you have a volt meter?
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Cutting / Re: Laser module for cutting 3mm plywood
« on: October 26, 2020, 10:47:13 AM »
Sadly the 5.5W will be 11 times worse on focus. Perhaps you could get 11 0.5W, a bunch of mirrors and lenses and make your own.
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Cutting / Re: Laser module for cutting 3mm plywood
« on: October 26, 2020, 05:49:55 AM »
Another factor is some vendors are now listing the raw input power, not the effective optical power. Diodes seem to be about 15% to 20% efficient so a 20W might be more honestly labeled a 3W.
I have 1.6W, 2.5W, 3.5W 1.5W & 15W modules. The 1.6W provides the sharpest focus, 2.5W visibly worse but used daily, 3.5w & 5.5w useless. The 15W was the cheapest, is close to 2W output power, and came with nice optics.
I have 1.6W, 2.5W, 3.5W 1.5W & 15W modules. The 1.6W provides the sharpest focus, 2.5W visibly worse but used daily, 3.5w & 5.5w useless. The 15W was the cheapest, is close to 2W output power, and came with nice optics.
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General Discussion / Re: Odd behavior at low power
« on: October 25, 2020, 06:55:00 AM »
I agree that laser mode with M04 SHOULD help improve the situation. The problem occurs on;y on the leading edge of new rows. Mechanically the mechanism has to reverse direction at that point. I do not see any problems on a test pattern that gives the mechanism 2mm to accelerate prior to enabling the laser. Time for "better' test. Attached is the file that exhibited this condition. The left edit of the "P" and the right edge of the "A" should the worse. Under the microscope it is every other row.
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General Discussion / Re: Odd behavior at low power
« on: October 24, 2020, 09:24:57 PM »
Switched to using a test pattern that is good for showing individual lines.
While in laser mode lowered acceleration from 5,000 to 2,000 and test pattern looks worse. Upped to 10,000 and it looks better.
Beginning to suspect that the quick reacting paper is part of the problem. If I up the power level I get more consistent results. Tomorrow will also see a change in the power supply.
BTW - laser lines look really crappy under a microscope!!
While in laser mode lowered acceleration from 5,000 to 2,000 and test pattern looks worse. Upped to 10,000 and it looks better.
Beginning to suspect that the quick reacting paper is part of the problem. If I up the power level I get more consistent results. Tomorrow will also see a change in the power supply.
BTW - laser lines look really crappy under a microscope!!
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General Discussion / Re: Odd behavior at low power
« on: October 24, 2020, 05:43:47 PM »
Using M04. Should this work in non-laser mode?
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General Discussion / Re: Odd behavior at low power
« on: October 24, 2020, 05:37:22 PM »
Will check. Disabled laser mode and the entire line seems to be burning darker. Wondering if there is something wrong with acceleration. My fixture is a core-xy.