wanting to pull trigger on dual head chinese machine

[daniel coyle]

After a fair bit of looking and comparing I found a lot of good options with the help of this and other forums. Came down to Shenhui and Weike in the end. Still no clear sense that one is better than the other but one has to choose. Any last convincing bits are welcome.

Mostly, I wanted to ask a little about the dual head option. I don't really think i NEED dual heads but it seems like a good way to get a backup tube AND have the ability to make use of it at the same time (rather than it sitting on the shelf, lonely.) My plan is what I need feedback on. Mostly need to cut .25 inch cork and, ideally, two sheets at once to increase productivity (I have only outsourced this before and so won't have hurt feelings if told I am way off on any of this). right now I am considering one 150W laser and one 80 OR 100W laser. The reason for this is because I have gotten the sense from the forums that 150W lasers are not great at engraving and while engraving will not be my priority I do expect to do some.

am i correct in my understanding about laser power and engraving ability?
is the difference significant enough to worry about or can one do reasonable engraving with 150W.


The following are the specs on what I am generally thinking of. Feedback welcome.
1300x900 table
Dual head design with RECI 80W and RECI 150W tubes.
One spare RECI 150W tube
Mechanical table with limits switches on all 3 axis
DSP Controller with Laser Cut 5.3 software
Dual linear guides and stepper motors
One spare set of belts for the steppers
Auto Focus and Red Dot tools
CW 5000 water chiller for each laser water chiller with pump and flow sensor
50, 63.5 and 100mm lenses
2 sets of mirrors, highest quality
Power z-axis bed with Stepper motors - must include limit switch
Cylinder Rotary
Irregular Rotary
Red Dot alignment - type that mounts on the laser head
Exhaust Fan (sucks the smoke out of the machine)
Air assist (blows the smoke away from lens)
Lighting on inside of enclosure – LED on the rear of the inside
Home position in top left corner (limit switch goes there)
Machine color - Red with Black doors

[Mohammed Issa]

hello Daniel,

im pretty new to this whole experience. my laser is on the way from Bodor (my first laser). and the only thing i can suggest, and im not sure if anyone else agrees, is that its really not a good idea to get an extra tube that you will not use.(im not sure if this still applies to RECI's) i have learned that they leak with time. i wanted to get a spare tube with mine, but then i was told if i do, it might lose some of the gas by the time i want to use it. therefore, its more affordable to buy it and ship it, when i know i need it. so if your not going to be using the dual head much, i would suggest not to get it. and dont forget that air freight is pretty quick (if your tube fails for some reason, it would take less than a week for the new one to arrive from china).

hope that helps.

[Chuck Stone]

funny you should mention the Bodor, I just looked at one but couldn't find any independent
info on them. (just alibaba and such..)

[Rich Harman]

I would also ask for an access panel by the first mirror. It makes it a lot easier to work on the first mirror.

And I would add a spare mainboard, LCD, stepper driver and stepper motor - but if waiting for replacement parts doesn't affect you, maybe not.

As far as getting a spare tube, one other thing to consider is that there seems to be a fair chance of damage to tubes that are shipped by themselves - ask Greg F.. I don't how my spare Reci will perform when/if needed but the cost for the 80 watt tube was not that much when compared to how much it would cost to airfreight one later.

I have mixed feelings about a dual head setup. On the one hand you can get the benefits of better engraving along with high power cutting. The tradeoff is a more crowded machine (harder to work on), different work envelopes for each head, double the moving mass on the X axis, and reduced effective table size.

Have you tested cutting cork with the 80W - with a 2.5" lens? I still have doubts that you need 150W for cutting 1/4" cork. If you have a sufficient volume of work then a dual head 80W Could cut two pieces at once, and be able to engrave well - at significantly lower cost.

If you really need 150W then if it were me, I would get a dedicated high power machine and a second smaller machine for engraving. A dual head machine sounds cool but I think that it should be avoided unless there is a demonstrable need for it.

[Rodne Gold]

I would (and did) go for 2 machines , 1 80w for cutting mainly the other a smaller 60w for engraving. 150w tubes are real expensive and might be overkill for your ap..
Get spare tubes and a full set of spares that will cover both machines.*like a spare motherboard that can be used on either* most parts are interchangeable
There a lot of shenhui users here who can offer an extra measure of support. I got amazing support from shenhui themselves , I think RDCAM/Laserworks is a better software than lasercut..but it's up to you who you feel more comfortable with.

[daniel coyle]

Thanks for the great advice. This forum is saving me from myself!
Seems to be some different ideas about the shelf life of sitting lasers. As for the cork, I have been unable to cut all the way through with 40 and 60W epilogs and have had an easy time with a 100W kern (might have been the lenses/focal length though, huh? ideas about ideal lens size welcome). Was able to cut two layers of .25 with a 150 kern.
Can 150 W lasers engrave in any sort of quality?
Right now the finalists are Weike and Shenhui though I have better quotes from Nanjing Diding and Triumph (and less references as well.)

[Rodne Gold]

You wont get fine work with a 150w tube. Spot quality is generally not that great for engraving. The real issue is that they can't fire properly and reliably at under about 15% power and the chinese lasers are "slow" (compared to faster mainstream lasers)...so you might find that 25w will overpower a lot of stuff--you wont get the laser fast enough to use such high power.
Shelf life of tubes seems to be ok , I recently swapped out my 80w RECI with my spar - 18 months on the shelf , and it worked just the same as the one I swapped it out with , which was the same as the day I got it.
You would probably have to use a 3-4" lens to cut thru 1/2" (2 x .25) cork , but the cut width will be significantly bigger than with a 2" lens as the spot size increases with the longer lenses..but you can compensate for that in the laser driver software.
You should be able to get something like a 130-150W Reci machine with a 1200x 900 bed size and a 600 x 900 60w machine , with a raft of spares (tubes , motherboards , lcd display, lenses , mirrors , stepper motors , stepper drivers , belts etc) for round $12-14k including shipping. There is a sticky thread at the top of the forum , read it and follow the links mentioned in it , tons of info there.
Go with established recommended makes , NOT price..I have never heard or seen the other makes you mention (not to say they bad..)

[john banks]

The most common thing we cut is 1/4" wood with a 3" lens at about 20mm/s for tulip or meranti, 15mm/s for walnut, 13mm/s for oak. We would not choose to double the thickness and halve the speed but just cut individually for better quality in the same time. I would imagine cork would be easier.

[Bob A Miller]

Dan... Little to add. Rodney is bang on I think.. Shenshui or Gwieke. I just did some sample cuts on 5 mm cork tiles with my 100w... Came out reasonably ok. I can get ok engraving (but I am not doing comercial) but lower W is still better for all the above reasons.

Bob

[daniel coyle]

Thanks. Still just amazed at how helpful this is. Rodne, really helpful, to the point, breakdown. I will check out the thread. Bob, thanks for the feedback on the cork cutting. John, for what its worth, the funny thing i have found with cork on all 4 machines i have outsourced to, it is harder to cut well than woods of similar thickness. I really liked the point you made about cutting for speed rather than trying to cut two layers. Hadn't thought of it that way.

Feeling ready to make a decision. Will share my experience when that happens. Thanks again.