[aussiemate]

Hi All

I've been reading quite a lot and I'm impressed with the support and advice given on this forum, well done.

I have however, struggled to find what is the best laser cutter for my needs, so I'm hoping someone can make some suggestions.

I wish to be able to cut puzzles out of high grade (AKA dense) birch plywood. the majority of plywood will be 6mm thick, but I am hoping to make some raised puzzles using 9/10mm plywood. I need at least 300 x 400mm laser bed, but am looking at slightly larger for increased productivity - no higher than 900mm though

I'd love to be able to afford a laser with the synrad laser, but unfortunatly my budget doesn't reach that far. Instead, I'm looking at eithe r buying from a couple of Australian companies that distribute the chinese models. (Rapid Concept or Red Dot Machinery), or purchasing from wklaser.

1. What laser cutter would best suit cutting plywood, while leaving a smooth thin cut line between the puzzle peices?

2.Am I better going with a 60W for a smaller line or an 80W (or higher) for more power (I understand the cut line becomes bigger the higher the wattage?)

3.If higher power means wider cut line, is there anything you can do to make the cut line smaller? (i.e. different lenses to make the beam smaller?)

4.What options in a laser should I be looking for?

I am quite technically minded when it comes to high tech equipment, as I used to be an analytical chemist and instrument maintainer, but for UV and Infra Red lab based equipement....laser cutters is a whole new ball game for me.

Thanks in advance for any help!!

[Tweakie]

It would be a good idea to ask the potential suppliers of your laser this same question.
My experience with plywood has not been 100% successful mainly, I think, due to the glue used to bond the layers. It tends to ignite making the kerf wider and causing excess charring of the cut edges when using just air assist. When I manage to obtain a bottle I will try nitrogen as the assist gas and see if that improves matters.
I would suggest the higher wattage laser would be better for your needs but be prepared for the cut edges to be sooty.

Tweakie.


This is typical of the sooty edges I am getting with wood by just using air assist.

[zax15uk]

Hi aussiemate, as Tweakie mentioned the wood portion is relatively easy to cut but the epoxy resins can be difficult. This is especially true for the exterior grade materials where the resin will usually burn and could produce toxic gases.

I would suggest a higher power CO2 laser (80W minimum) for this application, something like a 120W would allow a fast feed rate and reduce the burning.

The kerf can be reduced by using the correct optics, although this typically reduces the DOF which is not desired. A solution to this is a double lens arrangement to get the longer DOF and a small spot size, but of course this costs more. The 120W could be 2 x 60W tubes with a combiner so spot size may not be too much of an issue.

Using an inert gas will reduce the edge charring and can be very effective, air assist will help but usually won't eliminate it completely (except on thinner materials).

Selecting a good quality ply with water based eopxy may be enough to achieve suitable results depending on your finishing techniques.

Zax.

[zax15uk]

[QUOTE=Tweakie;799742]This is typical of the sooty edges I am getting with wood by just using air assist.[QUOTE]

Tweakie,

Nice work!

If you reduce the frequency (PWM setting) for the laser and increase power do you see any improvement? Increasing feed speed would have a similar result.

It may result in a striated edge but would avoid the heavy charring.

Zax.

[SunnyChu]

Hi aussiemate,

How are you?

We are china professional manufacturer for laser machine,
and I suggest you larger power laser machine, 80W or 100W.

we have 400x600mm, 600x900mm and 1200x900mm work area,
three phase stepper motor,
DSP control system
Import linear guideway
with best price and high quality.

Miss Lisa
www.jdcutters.com
E-mail: [email protected]

Hi All

I've been reading quite a lot and I'm impressed with the support and advice given on this forum, well done.

I have however, struggled to find what is the best laser cutter for my needs, so I'm hoping someone can make some suggestions.

I wish to be able to cut puzzles out of high grade (AKA dense) birch plywood. the majority of plywood will be 6mm thick, but I am hoping to make some raised puzzles using 9/10mm plywood. I need at least 300 x 400mm laser bed, but am looking at slightly larger for increased productivity - no higher than 900mm though

I'd love to be able to afford a laser with the synrad laser, but unfortunatly my budget doesn't reach that far. Instead, I'm looking at eithe r buying from a couple of Australian companies that distribute the chinese models. (Rapid Concept or Red Dot Machinery), or purchasing from wklaser.

1. What laser cutter would best suit cutting plywood, while leaving a smooth thin cut line between the puzzle peices?

2.Am I better going with a 60W for a smaller line or an 80W (or higher) for more power (I understand the cut line becomes bigger the higher the wattage?)

3.If higher power means wider cut line, is there anything you can do to make the cut line smaller? (i.e. different lenses to make the beam smaller?)

4.What options in a laser should I be looking for?

I am quite technically minded when it comes to high tech equipment, as I used to be an analytical chemist and instrument maintainer, but for UV and Infra Red lab based equipement....laser cutters is a whole new ball game for me.

Thanks in advance for any help!!

[Tweakie]

Aussiemate,

Most of the laser sales sites show pictures of their work in a gallery - It is perhaps interesting that plywood jigsaw puzzles are extremely rare yet it seems such an ideal thing to be laser cut.
There are plenty of laser cut acrylic jigsaw puzzles on show but I have yet to see a plywood one. Perhaps the charring is an issue.

Zax,

I have not yet implemented PWM control so it is just power and speed. Increasing the feed-rate does, as you say, reduce the charring but at the expense of not cutting all the hard parts of the wood-grain - it's a pretty fine balance here.

Tweakie.

[vlada2]

Tweakie,

please can you post a picture of plywood which was cuted with Nitrogen?

I tried eliminate flares with high pressure air (about 150 bars, from scuba tank) it looks better then air assist, but it also not be 100%

Thank you

Vlada

[Tweakie]

Hi Vlada,

please can you post a picture of plywood which was cuted with Nitrogen?

Haven't tried it yet but I will when I can get my hands on a bottle of nitrogen.

Tweakie.

[vlada2]

ok, so i will try it too Thank you

[Litografa]

Hi, Vlada
What is type of your laser?
For tests you can rent small (5-15 liters) tank of inert gas like argon, crypton and etc. I have made tests on 12 mm silicon rubber and diffirence with/without inert gas was unbelievable.
Many of my customers use nitrogen/CO2 for paper cutting - will try post pictures here later (if I will find them)

[vlada2]

Hi Litografa,

i have Chinese 80W JCUT.

I have inert helium and argon for diving, but it cost much more than nitrogen or argon, so i must take few litres of nitrogen

Hi, Vlada
What is type of your laser?
For tests you can rent small (5-15 liters) tank of inert gas like argon, crypton and etc. I have made tests on 12 mm silicon rubber and diffirence with/without inert gas was unbelievable.
Many of my customers use nitrogen/CO2 for paper cutting - will try post pictures here later (if I will find them)

[Litografa]

I know, but if you want make tests - it's ok test with inert gas, and use nitrogen for commercial orders.

[avetek]

Aussiemate

I have an 80watt laser and I can assure you that it will not cut 9 mm ply - with the standard lens - it will just cut 7mm ply. With a 3" lens it will cut the 6 mm ply reasonably easily. The charring that most plywoods have is due ,in my experience, to the glue (water resistant) - I only use indoor grade ply which cuts fine - this has a different glue that doesnt char.
I would think that you will need at least 1oo - 120 watts and buy a 3 in lens - this will give you a longer focal length , less kerf and hence a stronger cutting beam - I can cut at about twice the speed with the 3" lens vs the 2" std lens

Regards,

[Litografa]

Are you sure about 3" lens? Standart sizes are 1.5", 2" and 4"

[avetek]

Yes, it is a 3" lens - I bought it as an after market item from EC Laser in China - the focal length jig I made is 79 mm (as opposed to 54 for a 2"lens)

[rayscott]

My recommendation is to use lots of air assist.. preferably to have Nitrogen or even CO2 as the air assist gas. Using a Chinese machine will waste a lot of the air assist as it isn't well focused jet of air.

The kerf is directly related to the optics and time the laser is applied on the target material. The wattage is not the problem to increase the kerf size. Get focused... cut hard and fast with lots of air assist. Use a iron based honeycomb backer( the aluminum will reflect and cause a "spur").

Ray Scott
www.rabbitlaserusa.com

[aussiemate]

thanks for all the replies everyone.

I see now that I will have to stick with my maximum 6mm plywood (had hoped to stock a range of raised (using 9mm ply) puzzles, but it will be easier to glue 2x6mm together.

I have had my plywood texted on a desktop 500 WKlaser (Australian stockist) and it burnt too much - I'm waiting for the samples to come back, but will add the photos on here.

So... you have all suggested using nitrogen in place of air assist, and changing the lens. Is this easy to do on a chinese laser?
I'm technically minded, and not afraid to get my hands in to change the machine around (thinking of a 6090 80watt model, or the desktop 500 series with an 80 watt lens if it has air assist).

I am basically in 2 minds. I 'want' to buy from an Australian distributor so i can get the support as I am new to this industry, but I need to keep the laser TOTAL cost to below $15000 AUS. So, if I can get the machine to do what I need from Australia, I'll need to look at importing one.
The problem with importing one is I will not have the support and guidance on how to set up the laser with new air assist and lens suggestions made in this post.
I don't even know where to get the parts.

I have been looking at international laser companies, and have found a thread that suggests the following - WKlaser (Rapid concepts in australia I presume use these, and they tested my sample), Rabbit - Ray scott for English version Zhongtai laser, www.lltcorp.com and I also need to check out qwike, lg6040 but don't know if they're any good or not.

I have tried making contact with the above companies, and other than Ray, I am yet to hear from them

Epliog and the like are out of my price, and the laserpro spirit would be a look in but it's still just outside of my price bracket.

(I've made a 'learning post' and have a question on there about the differences between lasers RF/water sealed, so can anyone that can explain please pop over to my new thread and explain, cheers!!)

[Litografa]

Hi,
My advice is contact Gary Chapman from www.signtechnologies.com.au
First of all may be he can offer you used GCC laser or Chinese laser wih good support

[aussiemate]

funny you should say that Lingrafa, as I was online last night Gary contacted me (I'd spoken to them before but their new lasers were out of my price range)

I'm sending him samples today so he can check for me.