Benbox Laser Machines/CO2 Lasers/3D Printers

General Category => Inspiration => Topic started by: pbucc on March 01, 2018, 03:33:16 PM

Title: First real test
Post by: pbucc on March 01, 2018, 03:33:16 PM
Hi everyone first real test done. This is a heavy card stock and it took about 30 min. I didn't get the laser for cutting but I wanted to try it out.  The next step is to do a logo that o made a long time ago in illustrator.  I'll post some images of that.(https://uploads.tapatalk-cdn.com/20180301/54264e28bc30328dcccf7537e7362776.jpg)(https://uploads.tapatalk-cdn.com/20180301/2cf1499ddc321e494104baae84a1b6a8.jpg)(https://uploads.tapatalk-cdn.com/20180301/5cf37bf3d4e77c7f77309cf1b8231256.jpg)

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Title: Re: First real test
Post by: ianchia on March 01, 2018, 04:15:49 PM
👏🏽👏🏾👏 nicely done. Good to see the calibration worked.
Title: Re: First real test
Post by: Zax on March 01, 2018, 04:16:12 PM
That's a really nice clean cut. It took me months to get results like that, but of course I had to write the software first  ;D

Title: Re: First real test
Post by: pbucc on March 01, 2018, 04:17:36 PM
nicely done. Good to see the calibration worked.
It did. Thanks you for the help. I am running issues with the logo. I'll post some pictures later.

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Title: Re: First real test
Post by: pbucc on March 01, 2018, 04:18:24 PM
That's a really nice clean cut. It took me months to get results like that, but of course I had to write the software first  ;D
I am only doing it because of your software.

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Title: Re: First real test
Post by: ianchia on March 01, 2018, 04:51:28 PM
@pbucc In the hope of getting *really* nice cutting on paper, card and <1.5mm wood veneer, I'm in the process of adding a vacuum bed to my A3, inspired by this design:

https://www.youtube.com/watch?v=5CR1srYGQg0

I've found for cutting paper and cardstock, air assist in general hasn't been all that helpful and sometimes detrimental. For wood it works great. I'll be interested to hear how it goes for you if you go down that path.

Maybe it'll give you some further ideas.

- Ian
Title: Re: First real test
Post by: ianchia on March 01, 2018, 04:54:33 PM
It took me months to get results like that, but of course I had to write the software first  ;D

@Zax - I for one am very grateful that you did. Kudos. 🙏

- Ian
Title: Re: First real test
Post by: pbucc on March 01, 2018, 05:24:18 PM
@pbucc In the hope of getting *really* nice cutting on paper, card and <1.5mm wood veneer, I'm in the process of adding a vacuum bed to my A3, inspired by this design:

https://www.youtube.com/watch?v=5CR1srYGQg0

I've found for cutting paper and cardstock, air assist in general hasn't been all that helpful and sometimes detrimental. For wood it works great. I'll be interested to hear how it goes for you if you go down that path.

Maybe it'll give you some further ideas.

- Ian
That is what I plan to do.  I'm going to raise it with a steel grate and use magnets to hold in place. Also an enclosure will help big time.

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Title: Re: First real test
Post by: pbucc on March 03, 2018, 07:26:37 AM
So here is a Griffondor crest on a glass sheet. I used a hatch fill using eggbot plugin. I think I should have used a solid fill. I painted it with craft paint.(https://uploads.tapatalk-cdn.com/20180303/fb72b7f104d33f43d5f218c6104bed5f.jpg)

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Title: Re: First real test
Post by: ggallant571 on March 03, 2018, 07:59:43 AM
Looks good. I use "Neon" colored cardboard for test patterns. Avail from Walmart as index cards or 8/x 11 inch sheets. Cheap and easily burns with low power or high speed.

Please describe the process of preparing and cleaning the glass. What power and speed?
Title: Re: First real test
Post by: pbucc on March 03, 2018, 08:21:14 AM
Looks good. I use "Neon" colored cardboard for test patterns. Avail from Walmart as index cards or 8/x 11 inch sheets. Cheap and easily burns with low power or high speed.

Please describe the process of preparing and cleaning the glass. What power and speed?
Sorry. 

So the glass is 4x6 from a picture frame.  Got 4 for $2. Cleaned with Windex. Painted it with a brush and acrylic craft paint. Burned at high power at 500mm speed. 

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Title: Re: First real test
Post by: ThothLoki on March 03, 2018, 08:55:42 AM
My settings are similar for sheet glass
Title: Re: First real test
Post by: pbucc on March 03, 2018, 08:58:16 AM
My settings are similar for sheet glass
I got them you in the wine glass post. 8]

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Title: Re: First real test
Post by: ThothLoki on March 03, 2018, 09:25:13 AM
Well then I must be doing ok!
Title: Re: First real test
Post by: pbucc on March 08, 2018, 09:32:58 AM
1/4 inch birch plywood from Michaels. 1000 speed. Full power(https://uploads.tapatalk-cdn.com/20180308/0d381f414682162597e3876641763d53.jpg)

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Title: Re: First real test
Post by: ggallant571 on March 08, 2018, 09:47:53 AM
Nice to see you making forward progress.

Some observations:
  1. I have found by experimenting that I get better results by applying a sealer/stain to the wood prior to etching.
  2. Get a  small air compressor to blow away the soot.
  3. The vertical edges do not look as sharp as I would expect.
  4. You may benefit by touching up the original. Nottingham82 has posted instructions.
Title: Re: First real test
Post by: oscyp on March 19, 2018, 04:45:29 PM
Wow... how you guys get such results in cutting?
I have EleksMaker 2500mW from Banggood but cutting the plywood is horrible....
I have a home made honeycomb bed ( used a lot of 9x19mm brass :D).
Also focused the beam the best I could.
But cutting 3mm plywood takes over 50 passes... no kidding 50!
Power is: 255, Speed: 200
The newest grbl 1.1e used with full T2Laser Software

what am I missing...?
Title: Re: First real test
Post by: pbucc on March 19, 2018, 04:57:16 PM
Wow... how you guys get such results in cutting?
I have EleksMaker 2500mW from Banggood but cutting the plywood is horrible....
I have a home made honeycomb bed ( used a lot of 9x19mm brass :D).
Also focused the beam the best I could.
But cutting 3mm plywood takes over 50 passes... no kidding 50!
Power is: 255, Speed: 200
The newest grbl 1.1e used with full T2Laser Software

what am I missing...?
Air blower. Keeps the char build up down.

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Title: Re: First real test
Post by: oscyp on March 19, 2018, 05:01:19 PM
Yeah I was thinking about that, however it is hard to achieve a strong narrow stream... don't have any good idea so far...
But I thought not having fan will make difference of 3-5 passes... not 40.... :/

btw, how to check if my 2500mW laser is really 2500mW? any test I could do?
Title: Re: First real test
Post by: pbucc on March 19, 2018, 05:06:00 PM
Yeah I was thinking about that, however it is hard to achieve a strong narrow stream... don't have any good idea so far...
But I thought not having fan will make difference of 3-5 passes... not 40.... :/
The paper took me 25 min.  Wood will take longer. There are a lot of posts on how to make one. I just ordered a fish tank air pump. I haven't put all together yet.

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Title: Re: First real test
Post by: Alan on March 19, 2018, 08:45:27 PM
Made my "Air Assist" out of a cheap airbrush compressor from Ebay and a needle from a ball pump

https://www.ebay.com.au/itm/Compressor-Airbrush-Kit-0-3mm-Dual-Action-Spray-Air-Brush-Gun-Art-Tattoo-Set/183135425740?epid=589280158&hash=item2aa3b8d4cc:g:BRAAAOSwhsVar3bt
https://www.ebay.com.au/itm/10-x-Football-Basketball-Soccer-Ball-Inflating-Needle-Valve-Adaptor-Air-Pingj9/272994087724?hash=item3f8fb7332c:g:FEEAAOSwux5YNOHk

If you need a larger diameter (more air flow) you could use something like this

https://www.ebay.com.au/itm/12pcs-1-5-13Gauge-Silver-Stainless-Steel-Glue-Dispensing-Blunt-Needle/192104829882?epid=866629347&hash=item2cba5713ba:g:T20AAOSwWktag2~x

To be honest though, while it works I think it would work better with a compressor with a storage tank so you get continuous airflow not pulsing like I am getting now. Thinking about buying 1 of these.

https://www.ebay.com.au/itm/1-5HP-Airbrush-Air-Compressor-With-3L-Air-Tank-Mini-Hobby-Stencils-Nail-Tattoos/112538452803?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649
Title: Re: First real test
Post by: oscyp on March 20, 2018, 08:27:26 AM
Here are some fresh tests from me, 3mm plywood, square 10x10 [mm]

Left column: speed 200, middle column: speed 100, right column: speed 300
Inside the square there are number of passes.
Only on speed 300 and >150 passes I could go through and the square is not over burnt.
The white color is the very intense light of a flashlight on the other side while scanning the results.

Front side:
(https://i.imgur.com/y2PQwMh.jpg)

Back side:
(https://i.imgur.com/IxvGq3K.jpg)

To be honest.... I'm not so happy... :/


---edit---


I did another run with 220 passes - then the square just fell off when I took the plywood. 220..... Took 30min to cut 1cm square.... :/
Title: Re: First real test
Post by: Zax on March 20, 2018, 11:05:49 AM
Are you using air assist and a raised honeycomb or grid base?

They make a huge difference to cutting.
Title: Re: First real test
Post by: oscyp on March 20, 2018, 11:12:20 AM
Honeycomb - yes
Air assis - no, would it make so much difference to drop the number of passes from 200 to 8 like the other people are saying about successful cutting through?
Or maybe I have very strong plywood......
Title: Re: First real test
Post by: Alan on March 20, 2018, 02:25:52 PM
You using common garden variety 3ply or Laser Ply?

Note: I use the common 3ply under my cutting grid to block my 10W laser.
Title: Re: First real test
Post by: oscyp on March 20, 2018, 03:13:08 PM
it's just a common 3mm ply wood from a building store - I have no idea what wood it is made from
Title: Re: First real test
Post by: Alan on March 20, 2018, 03:28:26 PM
The type of wood is not the problem.

From reading posts on here and other research I have done on the net, it would seam that the glues and possible air gapes in the mid layers that are the killers to laser cutting.

After trying this myself on 3mm ply from the hardware I could not get past the first layer of timber with 20 passes. Then finding that it only takes 4 passes at 200 to cleanly cut 3mm MDF, I kinda figure their right.



I'm still fairly new to this myself so can someone else confirm this please.
Title: Re: First real test
Post by: pedwards2932 on March 21, 2018, 04:46:01 AM
You definitely need to use plywood designed for laser......the glue causes problems.  I would also look into getting one of the glass lens instead of the one that came with the machine that seemed to help with mine.  Finally getting the focus precise is very important, you have to take the time to make sure you have the thinnest cut line possible.  I was able to cut in 4 to 5 passes at 100 mm/min with a small kerf.  The air assist has to be working properly to clear the cut for each pass.
Title: Re: First real test
Post by: oscyp on March 21, 2018, 05:14:23 AM

I'll test some other woods. Since yesterday I started considering if the glue could be a problem, so you're probably right.


And regarding the air assist - do you think it is good? https://www.thingiverse.com/thing:1688209 (https://www.thingiverse.com/thing:1688209)
Unfortunately it does not suit the new laser holder of EleksMaker well - needs some adjustment.
Maybe you know better solutions?
But I like the idea - looks very nice.


---edit---
oh, I found something that should suit: https://www.thingiverse.com/thing:2626593 (https://www.thingiverse.com/thing:2626593) :)


Btw. pls point me what lens are you talking about? I didn't find anything for EleksMaker...
Title: Re: First real test
Post by: pedwards2932 on March 22, 2018, 04:19:49 AM
Here is one similar to the one I got:  https://www.ebay.com/itm/1pcs-Collimating-Half-thread-Coated-Glass-Lens-for-405nm-Violet-Blue-Laser-Diode-/151895001627?hash=item235da5ca1b

I just cut some 1/16 balsa the other night and I spent extra time getting it to focus and was able to cut at 360mm/min with as fine a kerf as I have ever gotten so it truly makes a big difference getting the focus correct.  I think any of the air assists will make a difference especially on plywood.  I use an aquarium pump and some 1/8" aluminum tubing.  I have a small airbrush pump that I want to try but just haven't gotten around to it.
Title: Re: First real test
Post by: oscyp on March 22, 2018, 04:31:53 AM

I have just realized that the plywood I was cutting was actually a waterproof plywood with some hard epoxy glue in it... that would explain the difficulties.
I will try to cut the other dry plywood with urea-formaldehyde glue soon to confirm it was the issue.


As for the lens: I searched for similar parts and here is what I have found - https://www.banggood.com/Triple-Glazing-Focusing-Lens-Collimating-Coated-Glass-Lens-Blue-Laser-Diode-405nm-p-1035471.html?rmmds=search&cur_warehouse=CN (https://www.banggood.com/Triple-Glazing-Focusing-Lens-Collimating-Coated-Glass-Lens-Blue-Laser-Diode-405nm-p-1035471.html?rmmds=search&cur_warehouse=CN)


Seems to be even cheaper and a little bit better (half thread vs. full thread).


I am only concerned about the mounting - does it fit inside the focusing barrel or is it replacing it? (some pictures of how it looks like on your machine would be great!)
Title: Re: First real test
Post by: pedwards2932 on March 22, 2018, 04:55:56 AM
I believe this shows the different parts.....you just have to remove the old lens and put the new one in the focus knob.   I believe I was confused on putting the new one in because you threaded the slotted end in first.   I had to use some Teflon tape to tighten the threads when I put the assembly in the laser.  This made it so it wouldn't wobble as the threads are kind of loose.
Title: Re: First real test
Post by: oscyp on March 22, 2018, 05:02:37 AM
hmm the dimensions of these parts are the same, so I don't know

so is it possible to use the original knob to focus the new lens? Or with the new lens a screwdriver is needed?


Do you have any focused-dot comparison? Is it really worth replacing?
Title: Re: First real test
Post by: pedwards2932 on March 22, 2018, 07:50:43 AM
Yes you use the old focus knob,  You just thread the new lens in after removing the old.  It seemed to make a big difference for me.  Here is some info.....I have a G7 but haven't tried it yet because it has a different focal distance and I was getting pretty good results with the 3 element lens.


3-element lens (Standard lens, best for low power lasers)
3-element lens has a long focal length, low divergence and clean beam profile but it has a very noticeable output loss.

Advantage
Tight laser beam with the cleanest beam profile
Downsides
70% efficiency (1W diode = 700mw with it)

G2 lens(best power)
G2 is a high pass single lens which allows more laser light to pass through, it is the lens for maximum power and engraving.

Advantage
95% efficiency, small beam aperture, perfect for close range burning
Downsides
Increase beam divergence(thicker beam) and affects the beam profile

G7 lens(Most balanced)
G7 is the second best high pass single lens but it won't increase the beam divergence like G2 does. G7 has a long focus length just like 3-elements lens, a well balanced lens between 3-element(divergence) and G2(power).

Advantage
88% efficiency, long focal length and tight beam profile
Title: Re: First real test
Post by: oscyp on March 22, 2018, 09:30:13 AM

Oh thanks for the explanation! I think that your words are perfectly describing this picture:


(https://i.imgur.com/RQGme7C.png)


Anyway both linked offers doesn't say anything about the type of those lens. So how should I know?
However, I am not sure why high-power lens are making poor depth cuts...
Title: Re: First real test
Post by: oscyp on March 23, 2018, 10:15:40 AM
Ok, I have just made some tests with another type of 3mm plywood and it is far better. Here are the results.


Front side:
(https://i.imgur.com/iXhXIgV.png)


Back side (image flipped horizontally):
(https://i.imgur.com/cmu1PbA.png)


Front side again, after taking the squares out.
(https://i.imgur.com/WMIlseT.png)


Square cut with a speed / no. of passes:
300/40, 100/20 - felt off very easily, almost spontaneously
300/35, 200/25 - felt off quite easy, a very little force was needed to push them out though
200/20 - felt off not so easy, some force was needed to push it out, but it could be done without any damage
300/30, 200/15, 100/15 - felt off very hard, quite much foce was needed to push them out, they were also torn while extracting


Conclusions:
- type of plywood makes significant difference
- dry plywood made of urea-formaldehyde glue can be cut 4.5 times faster (using speed 300: 180 vs. 40 passes to the same result) than a waterproof plywood made of epoxy glue
- speed 100 is still way too much over burning for me
- surprisingly speed 200 is not so bad this time


I hope that some people find this post useful.


I wonder how air assist would affect these tests...
Title: Re: First real test
Post by: ggallant571 on March 23, 2018, 11:04:51 AM
A pressurized air stream will remove the char and extinguish any flames.
Title: Re: First real test
Post by: pedwards2932 on March 23, 2018, 01:47:08 PM
I really suspect something is off with your focus.....It shouldn't take more than 5 passes if you have a 2.5 watt.  Do you have BCL or T2?  I use index cards stacked to the thickness of the plywood and BCL to cut a series of focus lines until I have the thinnest line possible line. My reasoning is your kerf line looks burnt out because of the number of passes.  Also I would look into ordering plywood that specifically says for laser. I was using this{
https://www.amazon.com/gp/product/B01N5CHME9/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1

It says that it is for laser.
Title: Re: First real test
Post by: oscyp on March 23, 2018, 02:04:46 PM
Yeah, dry plywood with urea-formaldehyde glue is so called "plywood for laser cutting".

Regarding the focus - it is really hard to do it manually with a knob. I tried to get the best focus I could. Anyway, it is still only a visual check afterwards. I am considering to add a Z-axis, but this would lead to changing the controller board as well...
Title: Re: First real test
Post by: oscyp on March 23, 2018, 03:51:46 PM
Ok, I was so curious that I found a can of compressed air and was blowing it constantly while cutting.
Here is the comparison:
(https://i.imgur.com/hIy4m1D.png)

So air assist is indeed helping with burnt edges but it does not affect the cutting abilities at all.... same number of passes - same results but less burnt.
Title: Re: First real test
Post by: ianchia on March 23, 2018, 04:40:08 PM
If you use transfer tape or masking tape, you can eliminate most if not all of the charring.

I use this stuff:
"600mmx20m Low Tack Paper Application Tape / Transfer Tape for Sign Sticker Vinyl"
https://www.ebay.com.au/itm/600mmx20m-Low-Tack-Paper-Application-Tape-Transfer-Tape-for-Sign-Sticker-Vinyl/251368075287?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649

- Ian
Title: Re: First real test
Post by: oscyp on March 23, 2018, 04:44:47 PM
it looks like a usual paper tape (like for wall painting or so)
Title: Re: First real test
Post by: pbucc on March 23, 2018, 04:46:41 PM
it looks like a usual paper tape (like for wall painting or so)
It is. Even blue painter's tape would work.

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Title: Re: First real test
Post by: oscyp on March 23, 2018, 04:50:43 PM
Won't it burn itself? :D
Title: Re: First real test
Post by: pbucc on March 23, 2018, 04:53:22 PM
Won't it burn itself? :D
From what I've seen online when you cut its ok. And engraving burns the tape. You could try it and see if it helps.

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Title: Re: First real test
Post by: ianchia on March 23, 2018, 04:55:20 PM
The low stickiness of the the low tack tape is designed so you can transfer cut vinyl decals from one surface to another. And it comes in extremely wide rolls that work well for large panels (A3+ etc) if you're doing large engravings or cuts.

I stick the stuff on, and then roll over it with a rubber roller (typically used by printmakers) to remove the wrinkles and ensure a even consistent surface to engrave/cut. Works really well, and is easy to remove.

If you want to experiment on a budget, try using some white or green painter's masking tape on your plywood. With painter's tape, you just have to be very careful not to overlap (so that the tape is double in height), or leave gaps - that way you'll get a consistent surface to prevent charring. Some folk on the forum feel that blue tape works less well. I haven't tried.

I've never had transfer tape or painter's tape catch on fire, compared to wood surfaces (or worse - painted wood surfaces.) But I have always had air assist, and aim not to overburn a surface with too slow a feed rate.

Best,

- Ian
Title: Re: First real test
Post by: ggallant571 on March 23, 2018, 06:04:16 PM
I have had zero success with blue painters tape. Good results with brown.
Title: Re: First real test
Post by: nottingham82 on March 23, 2018, 09:17:11 PM
Ok, I was so curious that I found a can of compressed air and was blowing it constantly while cutting.
Here is the comparison:
(https://i.imgur.com/hIy4m1D.png)

So air assist is indeed helping with burnt edges but it does not affect the cutting abilities at all.... same number of passes - same results but less burnt.


Hey Oscyp.  What is your wood sitting on? if it is sitting on a flat surface, try raising it so only air is under the cut.  It helps the finish the cut by letting smoke escape.
Title: Re: First real test
Post by: oscyp on March 24, 2018, 03:40:35 AM
Hello guys,

@ianchia I'll try the trick with a painter tape today, I think I had one that is 5cm wide - it will be enough for testing.

@nottingham82 I have self-made honeycomb bed out of 9x19mm shells :D - works very well. Anyway I need to work on air assist. Unfortunately, I have no 3d printer to make some useful parts for it...
Title: Re: First real test
Post by: oscyp on March 24, 2018, 05:35:39 AM

Ok I did a test with a paper tape.


This is the result before taking the tape off:
(https://i.imgur.com/rwWDN8p.png)


And after taking the tape off:
(https://i.imgur.com/vG6Ik0u.png)


The last square just felt off. The rest - did not.
After using some force - the middle 2 squares also came out.
The very first one did not - even with quite a force...


So the tape is helping a little :)


PS this time the air assist was my hair-dryer :D
Title: Re: First real test
Post by: ggallant571 on March 24, 2018, 06:39:06 AM
I think the primary purpose of the tape is to help keep the soot off the surface of the uncut wood. I'm assuming that 100/15 is 15 passes at a speed of 100mm/min. What power laser do you have? What is the approximate distance from lense to work?
Title: Re: First real test
Post by: oscyp on March 24, 2018, 10:17:23 AM
yes 100/15 means speed 100 and 15 passes.
Laser Power is 2500mW
Distance from lens ca. 11cm
Title: Re: First real test
Post by: ggallant571 on March 24, 2018, 06:16:52 PM
We have similar setups but you seem to have a wider kerf and more char. Do you notice any difference between the X & y cuts? Particularity and angle on two sides.
Title: Re: First real test
Post by: oscyp on March 25, 2018, 07:45:31 AM
Yes I notice something like this on some engravings.
Unfortunately I have to focus the laser beam manually all the time. (I mean when changing the material).

What does it mean?

I'll do some tests later on today to show you.
Title: Re: First real test
Post by: ggallant571 on March 25, 2018, 05:53:04 PM
An angle that is cone shaped on all sides is due to the focus beam. Wider on either X or Y is due to the rectangular bean pattern. Slanted in the same direction for both X or both Y is the laser module is not vertical.  Just my observations!!!