UV lasers?

[Matt Turner (physics)]

Hi all,

Does anyone have any experience with UV laser systems? I've got a grant proposal in for an LPKF ProtoLaser U3. It has a 6W 355-nm laser and is specifically made for rapid production of circuit boards, but is marketed as a micromachining system. I'm just trying to get an idea of what else we'll be able to use it for.

Thanks!

[Dan Hintz]

I used an LPKF system back when all they had were rotaries... the PC boards took a few hours to create, but they were immensely useful for fast-turnaround prototyping. Making a couple of PCBs in a single day rather than killing off most of a week waiting for the board house to get you something was awesome.

The cheaper UV systems operate similar to the hobbyist UV light exposure systems with acetate sheets ran through the laser printer... but since you're skipping a few steps, it's much faster. PCBs are coated with a photopolymer, hardened with the UV laser like an inkjet printer/plotter, then etched. I believe LPKF's system does a direct etch of the copper on the board, as well as providing tooling for drilling holes. In the really expensive systems, it also provides metalization so you can plate the holes... fancy schmancy stuff.

[Dave Sheldrake]

Selective sintering Matt?

6 watts at 355! oooo very nice :)

cheers

Dave

[Matt Turner (physics)]

Dan - Yes, this system does direct engraving of the copper-clad boards. It does this either by direct ablation or by cutting hatching into the copper and using a defocused beam to make it curl off of the substrate. It can also drill vias (but not plate them :) ) and depanel the boards. They also have an IR system that can remove the copper but can't cut the substrate. We know it will be useful for PCBs; I'm just trying to come up with some good "off-label" uses for it :).

Dave - Great idea! I've toyed around with the idea of trying to do this with our CO2 system, but I hadn't considered doing it with this one. I looked around for a bit trying to find a system made for both SLS and micromachining and didn't find one.

[matthew knott]

Ive used them, very nice bit of kits to have, cold marking, able to do many substrates that a infrared just wont touch, the lasers can be a bit delicate as the non-linear crystals in them wear out over time, also dont keep them anywhere damp !!!! I integrated UV lasers made by DPSS, when they worked they where fantastic, tiny spot , maybe you can get some ideas from this http://www.dpss-lasers.com/samurai2.html
How much is a machine like that going cost out of interest $60-90k as a guess

[Matt Turner (physics)]

Matthew - The system's list price is $210k. More than our Kern, with 1/50th the work area.

[matthew knott]

Ouch, nice bit of the kit, and i suspect the software will be very user friendly and seamless working with gerber files and the like, but that is a lot of cash. Are you using it for pcbs?

[Matt Turner (physics)]

Yes, the price was more than I expected, but the LPKF software suite will be very nice to have. We'll be making the system available to students to use for making PCBs and cutting metal foils and sheets.

[matthew knott]

Ok buy these for $10 and save $200'000, what could possibly go wrong ?? :)

[Ernie Balch]

When I worked at a large research lab I had a number of 355 nm laser micro machining systems, some were home built, others were from ESI and Orbotech and a couple of other companies. They used various Coherent lasers in the 2- 10 W range. They are fun to use in research and prototype production. In addition to flex circuit production we machined silicon, glass, ceramics, kapton, ITO on plastic, and various metals like Ti, Cu, Sn, and SS. We even built some microfluidic circuits and did some surface machining of W - Re alloys. Things like epoxy and Teflon don't machine very well but most other things are ok.

[Matt Turner (physics)]

That's great to hear, Ernie. What research lab did you work at?

[Ernie Balch]

Matt, look for PM

When you test the machine before purchase. Make a CAD layout and inspect it carefully for some common problems. 1) How well do they knit together the galvo fields? I assume they have to scan out a field, then move unless they have coordinated moves with stage and galvo together.

How does LPKF suppress the first pulse? Without suppression a line would come out as a big crater (think lollipop on a stick). With suppression the first few pulses would be gone. The systems I had always struggled with that problem. For example the ESI had an extra galvo to flip in and catch the first pulse after any pause more than a couple of milliseconds. The problem with micromachining was that It would lose more than the first pulse. At high rep-rates it might lose the first 10 pulses. This meant that the CAD layout had to know what the rep-rate was going to be and the motion delays related to covering the field compensate for the lost pulses. In other words we never got it worked out and had to run test parts then redo the layout to compensate.

ernie

[Hellen Smith]

355nm laser are used widely these years. Do you have any other similar laser system to recommend ?

[Matt McCoy]

Hi Matt,

Interesting thread.

I've been looking at milling circuit boards with a small CNC. I thought this was pretty cool:

http://blog.inventables.com/2014/02/circuit-board-milling-on-shapeoko-2.html

[Matt Turner (physics)]

Hi Matt,

We actually have a dedicated PCB router in house (also made by LPKF), but it's slow, requires the user to be present for tool changes, etc., and is limited in what it can do.


Hi Matt,

Interesting thread.

I've been looking at milling circuit boards with a small CNC. I thought this was pretty cool:

http://blog.inventables.com/2014/02/circuit-board-milling-on-shapeoko-2.html

[Allen Rawley]

The UV lasers are good for prototyping and production of touchpanels. The touchpanel overlay is often made by placing a thin clear film of ITO on a clear substrate by plasma. We made a number of very large touchscreen panels using a fiber laser, but the drawback was that the fiber laser removal was more visible than the UV. The UV wavelength/laser is the laser of choice for ITO touchpanel work.

Touchpanels are more widely used now as signs at malls, stores, museums, and also on devices (large monitors for casino games, home use, etc.).

[Matt McCoy]

I stumbled across an article mentioning the IR machine this morning, if anyone is interested:

http://makezine.com/2014/03/21/advanced-pcb-making-for-the-people/?utm_content=buffer741df&utm_medium=social&utm_source=facebook.com&utm_campaign=buffer