Benbox Laser Machines/CO2 Lasers/3D Printers

Thinking about focusing halfway through the 3 mm plywood as you suggest ggallant571 ... I did not have 1.5 mm wood to hand so I tried focusing using one of my key marks (a hole the size of the beam burnt part way through). This had the benefit of allowing me to use a magnifying app on my mobile to see the focus area clearly without the light spot being too bright for the sensor. Adjusting the focus ring while watching through the app gave a clearly visible position where the 'flare' disappeared. I have a feeling that I might be focusing on the top ring of the hole rather than the bottom, even so it could be useful. Time will tell if this is reliable...

I have been experimenting with cutting 3 mm plywood with my 1.6 W Laserbot and have experienced a very large variation in 'cuttability' over a sheet. This was true both with Creative Deco Plywood described in the advert as perfect for laser cutting, and with Laser Craft Laserply. Both are 3 ply Birch and I guess have hidden variations in the middle layer.

I am going from 6 x 100 mm/min @100% power to say 8 x 50 mm/min @100% power on the same sheet of Laserply and still having to repeat some cuts in certain areas of the sheet. Is this common or should I be searching for some other cause?

BTW I have as a result been cutting key marks on the sheet to help with realignment when replacing a sheet on the bed. To do this I used the low power focus setting turned up to 50% and applied for a few seconds both at 'Home' and again further along the X axis. Then when replacing the sheet it became reasonably easy to align the low power 4% beam so that it disappeared down each of the very small holes.

Hi
in case someone may find this useful I am following on from my previous posts getting my Laserbot working and becoming acquainted with Ralph's Bencutlaser software.
Thanks again Ralph for your help in getting going...

The Laserbot has been moved to a hut in the garden and I have been experimenting with cutting 3 mm plywood.
My first step was to set up an air-assist.
This consisted of:

• a small aquarium pump and tubing
• a reservoir (small glass jar with a plastic lid)
• a piece of custom metalwork (see picture)

I found some useful bits of rigid plastic tubing which just fitted inside the flexible tubing that came with the aquarium pump, inside disposable spray bottles that had held surface cleaning fluid.

To reduce pulsing and vibration I constructed a reservoir by putting two pieces of the rigid tube through holes drilled in the bottle lid and attached the unit in line with the pump. This worked remarkably well.

Hi Ralph
Thanks for your advice regarding cutting plywood. I will work my way through....

Here I have attached a picture of my template for the heat bed adapter which I have just cut from card. I shall now try it up against the parts of the 3D printer.

Thanks again for your help with the toolpaths

Regards
Philip

Hi Ralph
Thanks for the comment.

Can you point me in the direction of which of your tutorials would be useful to me in order to get the 3 mm plywood cutting? I have seen that you describe how to cope with the grain direction... Do you have any suggestions as to a typical tool setting? Did you try this with the laserbot?

Regards
Philip

Hi Ralph
I think I have cracked the problem...
Attached below is the result of engraving on 160 gsm card, 300 mm/min @90%.

I thought the power module supplied with it looked a little weak, so I attached a much higher spec one with plenty of spare capacity. After all, stepper motors with likely induction effects could easily disrupt the stability of sensitive electronics!

Now I can go on to explore your software and work towards cutting out the heat bed adapter.

Thanks for your help
Philip

Thanks Ralph...
In the meantime I have looked at the mft file, experimented, seen the structure and rebuilt the list of Toolpaths. I have now loaded the Toolpaths I was unable to find before.
I must have used some incorrect sequence of key presses.

It seems to be working OK now.
I'll give it another run through just to be sure...

By the way you mentioned shortcuts to functions. Is there a list of them somewhere?

Lets postpone the join for the moment. I'll get back to you....

Regards
Philip

Thanks Ralph for the explanation and video description. I'll get back to you when I have had a chance to follow it through....

Much appreciated
Philip