Newbie- buying my first cnc laser cutter/engraver

[meathelmet]

I am looking to buy a laser cutter/engraver for hobby use. I have recently started designing and building puzzle boxes. Almost everything I am going to cut will be 1/8 to 1/4 plywood. I have seen units on Ebay for around $1000. Which I thought was very cheap. I do not know anything about laser cutting and I need to know if those cheap units would be good enough for what I want to do. If not what do you guys recomend I look into?

[zax15uk]

The $1k lasers would struggle in your application, although I wouldn't completely rule it out if budget is a major factor.

Ply can be difficult to cut due to the epoxy, so you would get a lot of charring on more than 1/8". 35-40W is sufficient with PWM control and air assist, so these machines could be modified to work or you could invest in a $2-3k machine (60-80W tube) which would be ready to go.

Zax.

[meathelmet]

Would it be better to cut solid hardwood instead of ply-wood?

[zax15uk]

It is much easier to cut, but of course lacks strength compared to ply so you have to determine if it is acceptable for your puzzle boxes.

Zax.

[kevinliutrade]

Originally Posted by meathelmet Would it be better to cut solid hardwood instead of ply-wood?

The laser machine cannt cut much better on solid wood than on ply wood.When the laser power is 60W,it can cut solid wood 1mm,but it can cut ply wood 2.5mm.If you want to cut the 1/8" to 1/4" Poly wood,I advise you choose the laser power is 80W.It can do that work well.We are a manufacture in producing laser machine, we can offer you this kind machine.this is our website:www.jnsenfeng.cn. you can go on it to learn our products.If you are interested in our prodcuts,pls write to me:kevinliutrade@gmail.com

[geekinesis]

i have a cheap 40w laser cutter (rabbit 3040)

Yes plywood is a struggle because of the epoxy.

However 1/8 hardwood is easy to cut and I am cutting up to 1/4 hardwood (walnut)

Power isn't really an issue with thin hardwoods. In fact for 1/8 wood you need to keep the power low to avoid burning. I have the settings for power at about 20% of full power and a speed of 20mm sec for 1/8 walnut. Then I get no charing.

With any more power you can cut thicker wood but there is always the risk of flareups and therefore charing. I dont think you need any more than 40w for 1/8 and 1/4 hardwoods.

I can cut thicker walnut up to 1/4 with either a slower speed or cutting two times.

I also made my own air assist nozzle for $20 which means I can cut with no charing at all and get nice clean cuts.

On the cheaper $1000 machines the size of the cutting area is usually 200mm by 200mm which may be too small and means you have to pre cut most of the material you put in the machine. I have an area of 300mm by 400mm which allows for more flexibility, although the machine is a lot bigger and heavier so you need more space to install it. The smaller machines can fit on a desktop

Oh, and if you get a cheaper machine make sure the software is newlydraw and not moshidraw or newlyseal, which cant cut vectors

[kewlkiwi]

Originally Posted by meathelmet I am looking to buy a laser cutter/engraver... to cut will be 1/8 to 1/4 plywood.

One thing to be aware of, especially for puzzle boxes, is that cutting ¼" material you probably wont get a nice 90º cut to the surfaces.
The laser beam is a cone shape, determined by the focal length of the lens. If you set the focus on the top surface, the cut will be wider at the bottom, and the thicker the material, the worse this will be.
Set the focus on half of the thickness may help, but it still wont be 90º.
\ /
/ \
A longer focal length helps, but reduces the power available.

You may end up having to cut oversize on all 4 sides of the parts, then sanding the edges square and to size - since puzzle boxes depend on fairly accurate sizing to work.
Been there, done that...

Bob

[geekinesis]

yes I agree. 90% cuts are a problem with any laser. I set my focus to half way or make 3 or 4 repeated cut changing the focus each time. The thicker the material the thicker your cut line ends up being because of the focus issue.
Its no problem for the work I do but I can imagine struggling with something that requires a lot more accuracy.

I want to get a longer lens eventually but haven't found a supplier in the UK

[meathelmet]

Thanks for all the info. somehow I knew I wouldn't to be able to get where I need to be for $1000.