IS 80w too much?

[Tom Schulze]

I'm looking to purchase my first laser engraver. I'm looking a the shenhui,
redsail, or jqlaser 900x600 with and 80W laser. I have a variety of needs for
engraving and cutting. But my main question here is can I reliable reduce the
power enough cut paper and engrave on paper, or will the 80W always be too
strong for use on paper?

Thanks

Tom

[Mike Null]

Tom,

Welcome to SMC. I'd first advise you to do a lot of reading of past threads. Recently there have been quite a lot of new buyers of that piece of equipment. Almost all have opted for higher power. Those of us who have other machines generally feel that you should buy all the power you can afford. You can scale back 80 watts to engrave and cut like it was a 25 watt machine but you can't make a 25 act like an 80.

Once you get involved you'll quickly find that there's a lot more you want to do with it than cut paper.

[Tom Schulze]

Thanks for the welcome, Mike. I know there is a lot more to do than cut paper that's why I'm opting for the 80W, however my wife is really looking forward to the capabilities of the laser to cut and engrave on paper and I don't want to get something that can't power down far enough to do that for her. I've read through quite a few of the forum posts and know that you can only go so low on the power of the laser before you start having issues so I guess I'm looking for people who have exposure to this need to see if they were successful in using an 80W at that low of power or if they have had issues.

thanks

[Rich Harman]

I would expect the 690 sized machine to perform better with paper due to it's lighter moving mass than the larger machines. My 80 watt Reci will reliably fire down to about 15% power but when vectoring I am limited to about 30mm/sec speed before squiggles start to show up. A smaller machine should be able to go faster.

[john banks]

Similar to Rich, with slight variations due to tube power and machine size... 100W RECI can engrave paper without burning through it if you raster, but not tried vectoring as it would surely cut through even though we use 50mm/s for all vectoring. It will reliably fire at 8% power. However, unlike Rich's 80W, it will not turn off without a little splutter from more than 30% power and this will leave marks on the trailing edge when rastering at high speed, you can't see this on many marerials, but on slate, acrylic, card or paper you see it and have to reduce the power. This is testing two tubes and two power supplies, they are all the same. The tube manufacturer suggest that 4mA is the optimal current for high speed engraving, whereas the normal recommended max on this tube for cutting is 26mA. Our 100W tube is a good choice for a slight bias towards cutting. It sounds like 80W is the all rounder.

For RF lasers you may well find that none of these are issues, but they do not feature in the machines you mention AFAIK.

So far we've not found a job that needs the power or size of our machine, but I'm sure it will come. Most of it so far is engraving fairly small items.

[Steven Cox]

SHowever, unlike Rich's 80W, it will not turn off without a little splutter from more than 30% power and this will leave marks on the trailing edge when rastering at high speed

Hi John, this sounds like a problem I had, I found that if you add a border about 5mm around the design and set it as a cut line in a different colour to the rest of the job, lets say yellow. When outputting set Yellow > output > NO and order its position as the last object to laser. Then splutter Gone!... at least in my case.

If you still get the splutter then try and set the yellow up so its outside of the job because the splutter occurs on the last object being lasered right as the finish point.

[john banks]

Will try, but my splutter is on every trailing edge where the laser turns off from high power when rastering. So it will occur inside the text "800", and it will occur in that layer even if there are other layers with different speeds and powers which follow. I think it is a limitation of the 100W RECI tube.