Laser cutter for stainless steel stencils - Page 1
Forum section: electronics / general

author: olkipukki
author_rank: Frequent Contributor
timestamp: February 17, 2017, 06:34:38 pm
content: The market is flooding with different sort of laser cutters and I wonder if somebody here own one to make in-house stencils.What is price and operation cost starts from for a reasonable cutter and how easy to operate/maintain it?Is it worth hassle rather than outsource to PCB house?Thanks

author: IconicPCB
author_rank: Super Contributor
timestamp: February 17, 2017, 07:12:49 pm
content: conventional CO2 laser will not touch stainless steel unless...There is a surface treatment for stainlesss steel whihc will allow the CO2 laser to mark / cut stainless steel. The treatment is a spray pack of some black concoction. Itis sprayed on and when cutting completed it is removed.Costs an arm and a leg.A more apropriate laser source capable of cutting stainless steel is a fibre laser source..A laser cut stencil cut locally in Brisbane willset you back at least a few hundred dollars. Owning and operating one.s own laser cutter might be economicaly viable under these costs. Asian sources will cut a stencil for a quarter of the price, With freight it works out at half the local cost. OK if planing in advance of a project, Otherwise local next day delivery may be essential.

author: rx8pilot
author_rank: Super Contributor
timestamp: February 17, 2017, 07:55:20 pm
content: I have never seen a 'low cost' laser that can cut stainless sheet. It takes a lot of power, excellent optics, and a specific wavelength to accomplish that.

author: olkipukki
author_rank: Frequent Contributor
timestamp: February 17, 2017, 08:11:57 pm
content: In Europe, a bit more than a week of waiting and you can get a spencil for $50, for extra 25/30% - just few days door-to-doorAny hint on a starting price for a decent cutter?

author: IconicPCB
author_rank: Super Contributor
timestamp: February 18, 2017, 05:35:17 am
content: 30Wattfiber laser will cut stencil happily.A 30 watt reasonable chinese fiber laser source a few thousand dollars.On top of that optics and movement.

author: IconicPCB
author_rank: Super Contributor
timestamp: February 18, 2017, 05:57:28 am
content: See Raycus fiber laser.

author: rx8pilot
author_rank: Super Contributor
timestamp: February 18, 2017, 06:50:55 am
content: I have a 45W CO2 Epilog laser that won't touch metal. I can use Cermark to mark the metal but that is it.

author: Fred27
author_rank: Unknown
timestamp: February 18, 2017, 10:53:28 am
content: A hobby CO2 laser can cut mylar solder paste stencils. As rx8pilot states, it won't make any impact on metals.

author: MagicSmoker
author_rank: Super Contributor
timestamp: February 18, 2017, 01:40:20 pm
content: Quote from: olkipukki on February 17, 2017, 06:34:38 pmNear infrared is supposed to be best for cutting stainless steel, so that means Nd:YAG and fiber lasers, which tend to be really expensive.BUT... kapton (polyimide) and mylar (polyester) both make very good stencils that can be used 100+ times and which can be cut with a cheap 30-60W sealed-tube CO2 laser. Epilog is one popular manufacturer of lasers that are good for this application, but there are others.That said, it probably isn't economical to cut your own stencils unless you are designing dozens of boards per year OR you are willing to pay a huge premium to get a stencil immediately, but since a stencil isn't worth much without a board, you would also need to have rapid board prototyping capability as well... All in all, it's probably best to get stencils made by, e.g.,http://ohararp.com/stencils/(no affiliation, just a satisfied customer of their kapton stencils).

author: olkipukki
author_rank: Frequent Contributor
timestamp: February 18, 2017, 03:05:37 pm
content: What is mean "really expensive" - are we talking 6 digits (and plus) or...as mentioned by @blueskull a cheapest starts from $15K, so $25-$30K will take us closer to a decent?Actually, I never tried kapton and mylar stencils (basically, any non-stainless steel). Would be okay for 0402 parts and similar?Not sure if I need this since $40-$50 will get me one from EU supplier (more or less as Chinese cost if include all taxes, risks, duties and shipping).How difficult to use and maintain a cutter? Are there a lot of changes and overhead (setup type, gerber-to-what-ever-cutter-accepted-format converting) to fit into an existing workflow?As today, I generate a fabrication output and send these to a PCB manufacturier(-ies).

author: MagicSmoker
author_rank: Super Contributor
timestamp: February 18, 2017, 10:35:37 pm
content: Quote from: olkipukki on February 18, 2017, 03:05:37 pmI've used kapton stencils for the initial prototypes of boards that had 0.65mm pitch QFP packages on them and the paste printed fine. I suspect going down to 0.5mm pitch would be risky, though. 0402 passives should be fine, too, but I never use anything smaller than 0603 so can't speak from experience.

author: DerekG
author_rank: Frequent Contributor
timestamp: February 18, 2017, 10:54:03 pm
content: Quote from: olkipukki on February 17, 2017, 06:34:38 pmI'm not sure how many you need to make but PCBWAY will supply you panelised stainless steel stencils for about US$40ea.

author: jpanhalt
author_rank: Super Contributor
timestamp: February 19, 2017, 12:43:22 am
content: Why does it have to be laser? Why does it have to be stainless steel (which alloy?)I am always reluctant to make a suggestion when someone with a problem tries to define the solution -- assuming of course that there must be good reasons behind that. Why not etch or reverse electroplate the metal template? Have you considered copper or even (maybe better) nickel instead of SS? After all, if etching gives you the resolution you need for the PCB, why won't it give sufficient resolution for the template?John

author: DerekG
author_rank: Frequent Contributor
timestamp: February 19, 2017, 02:41:14 am
content: Quote from: jpanhalt on February 19, 2017, 12:43:22 amIt doesn't have to be laser cut, but the stencil shops are set up for this as it quick & accurate.QuoteStainless steel is generally used these days as it is very hard & lasts a long time. I actually prefer brass screens as they are easier to handle .......... but brass is not so common these days. Brass will still manage a few hundred thousand operations (if they are looked after) before they need replacing.

author: IconicPCB
author_rank: Super Contributor
timestamp: February 19, 2017, 02:49:50 am
content: I sometimes mill a stencil in double sided FR4 material ( 0.2mm thick ) as used in multilayer core production.Would not use it on 0603 or finer pitch designs.

author: DerekG
author_rank: Frequent Contributor
timestamp: February 19, 2017, 02:55:11 am
content: Quote from: IconicPCB on February 19, 2017, 02:49:50 amYes, good thinking. We do most of our stencils in 0.2mm to ensure enough solder paste gets laid down on the board for reliability in automotive/vibration environments.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: February 20, 2017, 09:18:14 am
content: One possible route to low-cost metal stencils is photochemical etching - some commercial stencils are done this way.You still have quite a lot of process optimisation to get it right though.

author: awallin
author_rank: Frequent Contributor
timestamp: February 25, 2017, 10:59:51 am
content: check this... plastic fantastic stencil with chinesium 40W co2 cutter

author: richardlawson1489
author_rank: Regular Contributor
timestamp: March 15, 2017, 10:26:16 am
content: Here is a reference for you, which may help you to find the Laser cutter.http://hackaday.com/2015/04/03/cutting-smt-stencils-with-a-laser/

author: D3f1ant
author_rank: Frequent Contributor
timestamp: March 30, 2017, 02:36:58 am
content: So does anybody know what the cheapest laser machine is that will cut stainless stencils?

author: Smallsmt
author_rank: Frequent Contributor
timestamp: March 30, 2017, 05:11:30 am
content: I don't know if it's cheap but GCC has good quality machines.Please look athttp://www.gccworld.com/goods.php?act=view&no=22

author: Spikee
author_rank: Frequent Contributor
timestamp: March 31, 2017, 10:04:03 am
content: Stainless steel stencils are soo cheap from china that seems crazy to invest in such machine.~15-20 usd for ~30*30 frame-less stencil 0.1mm thickness (0402, BGA... all ok) , DHL/FEDEX/SF EXPRESS/EMS/Cheap china AIR shipped within 36-72 hours.With about 20USD shipping cost for DHL to most places. Can probably even do combine shipping if your pcb also come from china.

author: D3f1ant
author_rank: Frequent Contributor
timestamp: April 03, 2017, 03:51:04 am
content: It's not so much about the cost, its the time it takes to get a replacement when there is design flaws. 2 or 3 days is a very long time to have machine sitting idle.

author: OSHStencils
author_rank: Contributor
timestamp: April 19, 2017, 11:33:54 pm
content: Thanks Blueskull, we do ship within 1 business day anywhere in the world and we utilize the best stencil cutting machine and metal on the market currently.Our pricing is linear, and you only pay for what you need. If you look on Twitter @OSHStencils you'll see lots of customer posted stencils, or our website in the gallery you will also see our product offerings.

author: jmelson
author_rank: Super Contributor
timestamp: May 14, 2017, 04:06:41 am
content: Yes, I make brass stencils form .003" brass shim stock, using the same technology for making PC boards. I use Riston dry film resist, making a set of mirror-image artwork. I glue the artwork in alignment, then slip the sensitized brass in between and expose and etch just like a PC board.Works quite well.Jon

author: janekm
author_rank: Unknown
timestamp: May 14, 2017, 04:33:25 am
content: BTW just the laser isn't enough to get good stainless steel stencils, there are post-processing steps too to remove the burr from the laser (otherwise the solderpaste won't release well). Usually electropolishing is used. You won't have much luck using an unpolished stencil for 0402 or QFNs (or smaller).LPKF are probably the best-known brand for the CNC laser setups for cutting the stainless steel stencils, and the better Chinese factories use their machines (there are also some good Japanese ones).So much like for making PCBs, it's a messy and expensive enough process that it's best left to a factory that do it day in day out and can reduce the costs to a minimum. You can just order the stencil at the same time as the PCB...

author: DigitalDeath
author_rank: Regular Contributor
timestamp: May 18, 2017, 07:26:29 am
content: I use a LPKF mill to mill 5 mil brass. They have 10 mil and 4 mill diameter end mill bits so you can make any size. Here's an example with several different footprints.You can get used LPKF mills pretty cheap on ebay and on top of that it allows you to make pcb prototypes.I would assume you can use pretty much any cheap chinese router engraver with these bits and make a similar one.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: May 18, 2017, 08:21:57 am
content: Quote from: DigitalDeath on May 18, 2017, 07:26:29 amHow do you keep the material flat while milling?

author: DigitalDeath
author_rank: Regular Contributor
timestamp: May 18, 2017, 08:26:57 am
content: LPKF mills have a "ring" around the mill that rests on the PCB while they mill. The depth of the cut is adjusted by how much the end mill protrudes from this ring. This head and ring are held down by a solenoid while the head is down.

author: IconicPCB
author_rank: Super Contributor
timestamp: May 18, 2017, 01:31:46 pm
content: What spindle speed and lineal feed rate do you cut at?

author: rx8pilot
author_rank: Super Contributor
timestamp: May 18, 2017, 05:15:28 pm
content: Quote from: DigitalDeath on May 18, 2017, 08:26:57 amThat is the only practical way to do the job with any hope of accuracy.

author: janekm
author_rank: Unknown
timestamp: May 19, 2017, 05:29:13 am
content: Quote from: rx8pilot on May 18, 2017, 05:15:28 pmAuto-levelling using a contact probe is also pretty effective, and arguably has some advantages:(and can be done on a much cheaper machine...)

author: DigitalDeath
author_rank: Regular Contributor
timestamp: May 19, 2017, 07:37:45 am
content: @IconicPCBFor the 10 mil (0.25mm) end mil I'm using 52000 rpm and 5 mm/s speed.For the 4 mil (0.1mm) I'm using 60000 and 4 mm/s speed.BTW the end mills are shaped for PCB milling so they have pretty short flutes and transition into 1/8 inch shank pretty quickly as shown in the picture below.@janekmThat software seems pretty cool. The only disadvantage that seems to me it would have is that you would need to secure the brass sheet to the base with double-sided tape or some other means such as vacuum. In the case of the LPKF that's not really an issue but then again you would need to get a used LPKF mill. I wonder if there is some gadget out there that does this same ring thing with a regular milling spindle. I bet it could be designed and made into a practical thing.

author: janekm
author_rank: Unknown
timestamp: May 19, 2017, 08:54:57 am
content: Quote from: DigitalDeath on May 19, 2017, 07:37:45 amYes that's right, normally one would use double-sided tape but it's a bit of a pain to peel off if one was doing this every day. It's fine as an emergency method (which is what I think PCB milling is good for anyway).

author: IconicPCB
author_rank: Super Contributor
timestamp: May 19, 2017, 11:54:30 am
content: Digital,I am familiar with LPKF tools. Excelent tools albeit pricey.Tools from precise bits are much less expensive and equal to the LPKF.I run the 10 thou ( 0.010" ) cutter for PCB work at 30KRPM and 1900mm/min on 1ounce copper ( 35 micron ). Another very interesting product Precise Bits have is cutting compound for copper.I guess Your LPKF has the 60KRPM spindle. Very nice ...but try to find the mechanically sweet spot of he spindle where run-out of the spindle will not provide excessive resonance and "smear" of the tool tip path.I run an Alfred Jaeger 100KRPM spindle but rarely push it above 50KRPM. Typically only when drilling 0.3mm holes .

author: DigitalDeath
author_rank: Regular Contributor
timestamp: May 20, 2017, 08:02:04 am
content: Thanks for the tip on precisebits.com it's part of Think & Tinker from which I purchased a plating line. I had not realized they had end mills. I'll keep them in mind for future purchases.

author: CopperCone
author_rank: Super Contributor
timestamp: July 04, 2018, 01:09:06 am
content: what kind of laser would you need to cut the brass stencil?

author: rx8pilot
author_rank: Super Contributor
timestamp: July 04, 2018, 05:37:22 am
content: 100mW cuts metal?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: July 04, 2018, 05:55:45 am
content: Quote from: rx8pilot on July 04, 2018, 05:37:22 amAvarage power of very short pulses - peak power is many kilowatts

author: CopperCone
author_rank: Super Contributor
timestamp: July 08, 2018, 10:43:03 pm
content: How about carbon fiber?

author: rx8pilot
author_rank: Super Contributor
timestamp: July 08, 2018, 11:19:22 pm
content: Quote from: CopperCone on July 08, 2018, 10:43:03 pmInteresting thought.....In CF you have various forms, each with different cutting approaches available.I have only seen raw CF and pre-preg cut with mechanical cutters. For cured CF, waterjet and mechanical works well.I have never seen anyone cutting with laser. My guess is that the huge temp tolerance differential between the CF and the epoxy binders would make it difficult to do well.

author: mrpackethead
author_rank: Super Contributor
timestamp: July 11, 2018, 06:14:02 am
content: I just bought a 300x400mm framed laser cut and electropolished stencil ex JLCPCB for $22. They make them really nicely and the job is just fine. They ship with my pcbs, and if you use LCSC.com for parts ( recommended ) they will ship them at the same time. Not something to even contemplate making.

author: CopperCone
author_rank: Super Contributor
timestamp: July 11, 2018, 04:46:22 pm
content: Is there any kind of metal that is a step up from plastic but still possible to cut with a cheap laser?

author: rx8pilot
author_rank: Super Contributor
timestamp: July 11, 2018, 04:50:34 pm
content: Quote from: CopperCone on July 11, 2018, 04:46:22 pmI think physics rules the world on this......it takes money to cut metal with coherent light. I have never seen a 'cheap' laser create the wavelength and power necessary to cut metal.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: July 11, 2018, 07:56:30 pm
content: If you really want to make your own metal stencils, photochemical etch is probably the only option.

author: IconicPCB
author_rank: Super Contributor
timestamp: July 11, 2018, 10:31:30 pm
content: Copper Cone,Under ordinary conditions a cheap CO2 laser will not touch stainless steel shim.There is a spray on treatment for stainless steel which will allow a CW co2 laser to mark the surface. I suppose repetitive ablation will eventually cut through, probably 20th pass.I can not recall the name of the product but have seen it in use, a friend was making tattoo machines out of stainlees steel and used to decorate the machine frames by laser engraving the polished surfaces.

author: 1276-2449-1-ND
author_rank: Regular Contributor
timestamp: July 22, 2018, 12:18:00 am
content: Chinese fiber lasers that can cut thin stainless sheets are around $5K now.I've been making stencils from mylar sheets on a CO2 laser cutter -- the trick is to ablate (etch), not cut away the mylar to get crisp edges with no bumps or burning.When the laser was down and I needed some quick stencils I got a cheap craft vinyl cutter and it also made surprisingly useful stencils (the trick here is to overcut the corners so nothing dangles or leaves a little nub).

author: mrpackethead
author_rank: Super Contributor
timestamp: July 22, 2018, 02:16:48 am
content: got a link.

author: mrpackethead
author_rank: Super Contributor
timestamp: July 22, 2018, 02:18:24 am
content: Quote from: 1276-2449-1-ND on July 22, 2018, 12:18:00 amI'm not familar with that technique? How does it work? Is it like a raster scan or something?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: July 22, 2018, 09:57:31 am
content: Quote from: mrpackethead on July 22, 2018, 02:18:24 amYes - you laser the whole area of the aperture rather than cutting round the edges.

author: beanflying
author_rank: Super Contributor
timestamp: July 22, 2018, 11:42:05 am
content: Quote from: 1276-2449-1-ND on July 22, 2018, 12:18:00 amHaven't got around to trying Mylar on my 40W yet but etching works well on light card and paper. I will run some tests on cut vs etch when I get some thin plastic loaded up.Still amazed how often people ask can xyz small laser cut 'metal' even Google knows the answer to that one.