Author Topic: Where to focus the laser before starting?  (Read 1003 times)

mrehmus

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Where to focus the laser before starting?
« on: April 04, 2017, 11:29:19 AM »
I wonder if it would make sense to focus the laser on the baseboard of the system and then input the thickness of the material. This would allow one to leave the laser focus alone most of the time and the Z-Axis system would then pull the laser up the thickness of the workpiece. This would also then setup the decrement of the Z-axis per cutting pass. The cutting depth of the laser during a single pass would be input just as one sets power and speed. Cut2D handles milling pass depth in this manner and it works out very well and is easy to use. It allows an override for # of passes if the user desires.
The steps would be to:
- First determine how deep a cut a single pass will make (depending on the material).
- Measure the material thickness
- Input both values into the Tool table.
- Assign the tool to the work
- Light the fire knowing that the system will decrement the Z-axis height after each pass
mrehmus
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Re: Where to focus the laser before starting?
« Reply #1 on: April 04, 2017, 01:25:17 PM »
As an FYI -- BCL automatically determines the Z drop per pass. All you have to do is tell it the material thickness and it already knows how many passes, so it can calculate the average drop for you automatically.want to.
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mrehmus

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Re: Where to focus the laser before starting?
« Reply #2 on: April 04, 2017, 01:54:33 PM »
Yes, I know that. That is what triggered the idea that leaving the laser focused on the baseboard and retracting the Z-Axis enough to focus on the workpiece would be better than continually having to refocus the laser.
mrehmus
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Re: Where to focus the laser before starting?
« Reply #3 on: April 04, 2017, 02:04:54 PM »
I almost always work with 3mm plywood and once I focus, I never have to focus for a very long time. I might be missing a point here, but I don't understand why one would not want to manually focus their laser? Are you constantly switching material thicknesses everyday? If not, then I guess I'm missing something in this thread. I might manually focus once or twice a month!
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mrehmus

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Re: Where to focus the laser before starting?
« Reply #4 on: April 04, 2017, 02:30:31 PM »
Yes I do switch material thickness as I cut a number of materials plus, when I start engraving, the materials will vary quite a bit.

Furthermore, I've looked at the mechanical arrangement of the lens in the laser carrier. The two O-rings will, sooner or later, wear or become cut by the threads and the lens will really rattle around like a BB in a boxcar. As you know, it isn't great when it is new.

Far better to not have to frequently focus the laser.
mrehmus
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Machine Shop with manual and CNC machines

treinbert

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Re: Where to focus the laser before starting?
« Reply #5 on: April 04, 2017, 03:11:32 PM »
Hi,

I also switch a lot between various materials and thickness.
So focussing on the thinest material is a very good option.
My machine with a working Z-axis is not yet completely finished.
I just soldered the control-board with some connectors, so I can swap controllers easily.
I also made a bypass to use a TTL-board or not.
I can switch with three kinds of lasers at the moment.
I test with the small one, 500 mW. The second is the standard 2500 mW non-TTL.
The one yet to test is a 3500 mW TTL laser.
Hartelijke groeten/Best regards/Freundlichen Gruessen,
Bert Mengerink

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