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Messages - PhilMC

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BenCutLaser / Re: Laserbot Marlin (CONTINUED) Plywood
« on: October 20, 2019, 11:36:50 AM »
Hi Krypton

The tubing I used was:
 Soft Copper Tube Copper Pipe OD 4mm x ID 3mm for Refrigeration Plumbing from Amazon.

So that's 4 mm rather than the 6.35 mm of 1/4 inch OD. Not far from your 1/8 inch on the inside.
Difficult to tell from a photo without a scale.

Perhaps your air pump needs cooling???

I used a rubber grommet to give a tight fit so that the copper tube was movable but also held in place. I think in an update I might make it two grommets as it still allowed a little rotation if the air line was dragged.

Best of luck with the jobs so you can get back to playing with the laser cutter. After all you might be able to make something for your truck!


BenCutLaser / Re: Laserbot Marlin (CONTINUED) Plywood
« on: October 19, 2019, 11:14:45 AM »
Hi Krypton.
Thanks for the comments on the air-assist mounting...

I have some Metalcraft tools and I used a narrow strip of their annealed steel (bms) to make the bracket.
The fixing to the laser heat sink is with some tiny bolts which just happened to have a tight fit between the cooling fins. I have built some drones, and they are spares from the motor fixing kits.
You are welcome of course to copy any of my ideas, that in itself is a form of flattery. :D

Best of luck with cutting 3 mm ply. In my brief experience I have found that whatever setting you choose and test, somewhere will not completely cut though and will need a repeat run (or two). Fortunately this is easy to arrange with Ralph's excellent software!

BenCutLaser / Re: Laserbot Marlin (CONTINUED) Plywood
« on: October 18, 2019, 11:23:00 AM »
I have continued to experiment with 3 mm laserply...
I found that cutting was best if I focused the laser on the surface of the plywood. If I used the method I used in my last note, cutting was not as good, so I don't think I can be focusing on the top of the hole. In which case it might be worth my trying with a hole which goes halfway through the material.

I am pleased to say that I have now successfully cut out the 'heat bed adapter' for my 3D Printer! :D  This was the aim that started me on the path to laser cut plywood.

BenCutLaser / Re: Laserbot Marlin (CONTINUED) Plywood
« on: October 13, 2019, 11:16:37 AM »
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...

BenCutLaser / Re: Laserbot Marlin (CONTINUED) Plywood
« on: October 13, 2019, 10:52:47 AM »
Thanks ggallant571 for your information and suggestions.
  • I currently have my laserbot on blocks to give 60 mm from lens to workpiece.
  • I must check that the beam is perpendicular as you suggest
  • I already have put in an air-assist as you can see in my post of October 07, 2019... but I noticed that the air alignment might be affected by the pull on the air line. To try and prevent this I have added a bracket today to the top of the laser unit. (picture to follow)

Experimenting continues...

BenCutLaser / Re: Laserbot Marlin (CONTINUED) Plywood
« on: October 11, 2019, 11:08:49 AM »
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.

BenCutLaser / Re: Laserbot Marlin (CONTINUED) Plywood
« on: October 08, 2019, 11:22:40 AM »
Thanks Ralph for the acclaim  :D
More to follow soon...

BenCutLaser / Laserbot Marlin (CONTINUED) Plywood (CLOSED)
« on: October 07, 2019, 11:49:08 AM »
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.

BenCutLaser / Re: Laserbot Marlin (OPEN)
« on: June 01, 2019, 12:13:26 AM »
Hi ggallant571

Yes thanks for picking that up. Its the old story of checking your own work... you see what you want to see!


BenCutLaser / Re: Laserbot Marlin (OPEN)
« on: May 31, 2019, 11:25:46 AM »
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


BenCutLaser / Re: Laserbot Marlin (OPEN)
« on: May 30, 2019, 11:07:15 AM »
Hi ggallant571
Thanks for the info...
The plywood I purchased from Amazon:
'Creative Deco 10 x A3 Plywood Sheets 3mm | 420 x 300 x 3 mm | Baltic Birch Wood Ply | Perfect for Pyrography, Laser Cutting, CNC Router, Modelling, Fretwork, Scroll Saw'

I am hoping that it lives up to its reviews!

I don't have an adjustable z or an air blower. The latter I might be able to rig up or make something with my 3D printer, or purchase from A. I guess I might need something with a nozzle and a pump, perhaps an aquarium air kit or a miniature paint spray. Any ideas?


BenCutLaser / Re: Laserbot Marlin (OPEN)
« on: May 30, 2019, 07:31:39 AM »
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?


BenCutLaser / Re: Laserbot Marlin (OPEN)
« on: May 30, 2019, 07:24:32 AM »
Hi ggallant571
I have a laserbot with 1.6W blue diode laser.
I was concentrating on getting complete lines without breaks as you can see from the dialogue. I have yet to experiment with speed though that will be soon! What do you use your etched colourstock for....?

BenCutLaser / Re: Laserbot Marlin (OPEN)
« on: May 29, 2019, 11:30:39 AM »
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

BenCutLaser / Re: Laserbot Marlin (OPEN)
« on: May 20, 2019, 10:50:59 AM »
Hi Ralph
Thanks for the shortcut details.
I must also say thanks again for the tutorial material you posted regarding the heatbed adapter.

I had a go with Main Test55 and cut it out of paper. A photo is attached.
As you can see there are bits missing!

I have also attached a photo of some tests I did adjusting the power setting. The rounded square is also incomplete.

I wonder if this is due to laser power-on delay? I saw this mentioned in a discussion you were having with 'svogl' on another forum about the laserbot.
I think it looks as though most if not all the missing portions are at the beginning of a cut?
Did you get this with the laserbot you built?


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