Stencil printer (essemtech) - Page 1
Forum section: electronics / general

author: mpbrock
author_rank: Contributor
timestamp: February 08, 2020, 09:21:31 pm
content: My new toy (essemtech semi automatic printer) has arrived and trying to figure it all out, it came with this frame (with a transparent material on it) but I’ve no idea what it’s for. Any ideas?Thanks in advance

author: SMTech
author_rank: Frequent Contributor
timestamp: February 08, 2020, 09:34:26 pm
content: Interesting, literally just bought almost the same toy. (I think bigger, no cameras)That's a mylar alignment aid, its in the manual as an option.Basically you put it over your PCB and do your first print. Now when you lift the stencil away you can see exactly how your print image aligns with the PCB beneath it whereas without it you can only see whatever the stencil apertures reveal to you. Now you can adjust the alignment against the print on the mylar, this is most helpful when you have an aperture shrink as when you have those you are otherwise unable to tell if you are dead center or towards one edge of your pads.In the manual I have for an SP003ML it only mentions it and goes into no real detail (but then it doesn't manage much of that anyway). You will find similar attachments on printers like a Reprint R23 or similar that often have a setup/alignment table to the side of the printing area.Essemtecs printers that look like this are in fact rebadged printers made by pbt-works.cz you can still buy some variants of them today and they have a pretty decent network of resellers who should (I think) be able to sort you spares etc. Later Essemtec printers came from Reprint (who they own a chunk of) but they seem to have stopped selling Essemtec branded printers at all these days. In the UK Zen now sell Essemtec and are the primary sellers of PBTs cleaning machines but not printers, printers are the preserve of KPE (who were the Essemtec agent) and PMTech.A bunch of used Essemtec stuff got put on eBay at the beginning of the year, almost all of it seems to have sold to the first bidder. Its not something I see on there often and I do try to keep an eye.

author: mpbrock
author_rank: Contributor
timestamp: February 08, 2020, 09:50:30 pm
content: Thanks :-) this is the SP-100 with the Motoprint vision option fitted. Manual seems rather sketchy and badly translated, hopefully not much to it. Takes 23” stencils - that’s problem number one - I haven’t got a stencil foil adapter for it (desperately searching for one at a good price). Don’t know if to try a Chinese jlcpcb stencil to get it going but my friend has advised they tend to be too thick compared to the expensive foil ones he gets done over here (Tecan).

author: SMTech
author_rank: Frequent Contributor
timestamp: February 08, 2020, 10:17:35 pm
content: We buy stencil foils from an agent who in turn buys them from Lingva in Slovenia, we have 23" fixed frame stencils from there too and they are a perfect fit.Our old Tecan frame is 430mm so too small without an adaptor, moving forwards we have two primary options a 23" Tecan frame (mechanical) or a 23" VectorGuard frame (pneumatic). The VG foils cost slightly more but have a protective inner frame that is permanently attached and the outer frame can need servicing. 23" fixed frame ones cost only slightly more than VG but take up way more spaceWith both frame systems I can have the supplier amortise the cost of the frame across the cost of the next 20 foils /12 months or some similar arrangement. We did this with Tecan when we acquired the 430mm one -it was a solution they offered.I don't think I've had an exactly 23" stencil from JLC/PCBway (always rectangular) but the big ones I do have, have been under 25mm thick. If anything a bit weedy.

author: SMTech
author_rank: Frequent Contributor
timestamp: February 08, 2020, 10:22:20 pm
content: Is this the £100 spares or not working unit that someone had shoved in a corner because it "took too long to set up?"?

author: mpbrock
author_rank: Contributor
timestamp: February 09, 2020, 02:05:44 am
content: Yeah! lol you spotted it too .. figured it was worth a punt.. cost me £150 to shift it though ..Might I ask was your sp003 in the same price region ? Not sure if I’ve done well or not! Built like a tank though, all seems present just need to figure it out!

author: SMTech
author_rank: Frequent Contributor
timestamp: February 09, 2020, 11:52:53 am
content: Yeah I wasn't up for the collection or the punt. Paid much more for the SP003 but much less than it was previously offered to us for, one number was tempting, one was not. I'd have said you got a steal, I know the SP150 was very well regarded (currently known as the FA23) but I don't just how much they added/tweaked between the two.The manual is truly awful but my primary concern is how much fiddling may or may not be involved in handling thicker PCB's.Its tempting to pull the crappy magnets out of the PCB holders and put in something a bit beefier.

author: mpbrock
author_rank: Contributor
timestamp: February 09, 2020, 03:09:44 pm
content: Wen you say thicker PCBs, I’ve not really thought about that before a double sided 1.6mm FR4 is going to be different to a 4 layer PCB thickness, so I guess the stencil needs to be lifted higher for the thicker multilayer pcb?I’m guessing the magnets in the vacuum holders aren’t very good then? I’ll have to keep an eye on that.

author: SMTech
author_rank: Frequent Contributor
timestamp: February 09, 2020, 04:51:52 pm
content: It's actually the two long rectangular edge supports I think could do with being more secure, but I won't know 'till I've actually tried it.Different thicknesses of PCB do indeed need adjustment to the stencil height and even that can change if you have a mix of stencil types. On the SP003 there seems to be crude adjustment using two massive nuts on the hinge and then there are four posts for finer adjustment. They looks like they may need some TLCThe alternative trick would be to make different support tooling for each PCB thickness so its the top of the PCB that's always in the same plane rather than the bottom.Toolkit also came with two shiny/mirror finish rectangular plates, no clue what they are for.

author: fcb
author_rank: Super Contributor
timestamp: February 09, 2020, 05:20:52 pm
content: Quote from: SMTech on February 08, 2020, 10:17:35 pmWhat sort of money are these framed stencils from your source?Those machines look less trouble than an old DEK with it's air hose/fitting wack-a-mole.

author: SMTech
author_rank: Frequent Contributor
timestamp: February 09, 2020, 05:59:26 pm
content: IIRC a 23" Vectorguard foil is about £140, a framed one maybe £180 and a framed one from Tecan perhaps £220 whereas a foil is more like £120. There must be several eastern european/asian manufacturers who give the many UK based ones a pricing headache. Back in the distant past all our framed stencils used to come from Alpha, they were quite expensive. Frames to take foils are in the £1500-£2k bracket, to us that's worth it just for the space saving we currently have quite a lot and a high number of new ones, the point at which they are no longer required is not always apparent.Oh and I suspect that might be before carriage...There are some minor advantages on a printer like this to an automatic when running small batches, the main one being you can do what the hell you want as the unit is pretty dumb, so if you want to scatter 4 or 5 different PCBs across the free space in your stencil, that's not a problem. They are also quite simple so there's less to go wrong.What you don't get:InspectionUnderwipe/blow/suck cleaningAutomatic alignment on every printMeasured squeegee pressure (well you might on some)Clever extras like extra paste/glue dispensing or serial number stickersCompared to a more manual printer you get:pretty decent PCB supportconsistent blade angleconsistent squeegee pressureconsistent blade speedVertical PCB lift/separationDecent size (23" seems less common on super manual printers)At the very top of the tree is the F23 Automatic which brings in automatic alignment and a kinda semi-manual underwipe mechanism while still being a standalone batch printer however its only 30% less than an ESE truly automatic 29" printer with a pretty decent set of features at that point.

author: Reckless
author_rank: Frequent Contributor
timestamp: April 21, 2023, 11:28:57 pm
content: Quote from: SMTech on February 09, 2020, 05:59:26 pmI got Essemtec SP-002M which has squeegee installed on top. Do you need to put air for the squeegee handle to move back and forth? How long does it take you to line up on this?I came across this for Essemtec SP002:http://www.zelflex.com/products/zelflex_z4p/558x558_584x558.htmlI am trying to find something like this so I don't need to buy/store frames:http://www.zelflex.com/products/zelflex_zr/There is also an air tensioned version but not sure which will be better?http://www.zelflex.com/products/zelflex_zr/http://www.zelflex.com/doc/LPKF_ZelFlex.mp4

author: Reckless
author_rank: Frequent Contributor
timestamp: April 22, 2023, 07:09:36 pm
content: Also, I need to buy a new squeegee, I found this company but trying to see if there are any others:https://metalsqueegees.com/products/metal-squeegee-with-holes-for-essemtec-sp-series?variant=32030580768821Does it use a compatible squeegee blade with some other models?Screw / Spring tensioning frame may be better than the Zelflex see page 8. Not sure if stencil will need holes in order to do tension?

author: SMTech
author_rank: Frequent Contributor
timestamp: April 23, 2023, 04:58:41 pm
content: Quote from: Reckless on April 21, 2023, 11:28:57 pmLine up time , gets quicker the more experience you have, if you have the mylar bit etc, but a few minutes should do it.I think the blade design and the holes are basically Essemtec (maybe also PBT) unique. One of my stencil suppliers had the dimensions on file, and could make them to order. You might find a local stencil supplier who can do the same. You could also get a crude one made in china by knocking up a gerber for JLC or similar.The squeegee is hand powered, as you pull the handle it tilts the mechanism and lowers the relevant blade to the stencil. For the next board you push it the other way and it uses the other blade. On the SP003 a belt and electric motor replaces your hand.The pneumatic part is the table, is drops down when the print is complete so that you have vertical separation of board and stencil, then you lift the stencil up on its hinge to remove the board.Your linked frame is essentially a 23" one, that would only fit if you have the SP002 ML, the non-L has a decidedly uncommon frame sizehttps://www.pmtech.co.uk/pdfs/TDS/Equipment/essemtec/SP002_Brochure_(En).pdfEssemtec has a system a little like the Zelflex one which of course would fit, if you could find it;).If you have an L there are a number of systems like this the most common being the DEK VectorGuard. On the SP003, the VectorGuard system is too thick for the default clamping system and you'd need to mod it. The brochure uses the wording "up to" however if the Sp003 model I have is anything to go by, its not adjustable, at least not on all models.

author: Reckless
author_rank: Frequent Contributor
timestamp: April 24, 2023, 03:02:19 am
content: Thanks for the clarification I have the L model (23"). How do you like your SP-003 with belt and electric motor vs hand lever? PBT makes so many interesting models, it's hard to pick one over the other.I'm just learning about Tecan. Which one did you like better the mechanical Tecan or the pneumatic vectorguard? On youtube there is a comment that the DEK vector guard breaks often. Is the mechanical tecan same as genesis?https://www.stencils.co.uk/smt-stencils/genesis/I'm leaning mechanical currently.

author: SMTech
author_rank: Frequent Contributor
timestamp: April 24, 2023, 07:46:27 am
content: I can easily and reliably get a correctly cut Vectorguard stencil from just about any stencil supplier, a Genesis stencil really needs to come from Tecan as the stress relief and alignment holes are pretty critical. I can and do get the elsewhere but it took some tweaking to dial it in so the tension was right.I don't think the Tecan frame is going to fail easily, however as it takes a floppy foil, its easier to damage that foil when handling it, or cut yourself and this is probably true about other similar systems. As a bonus of course they are very thin so you can fit several in a box, or invent your own hanger that holds them quite densely.Vectorguard is semi rigid so somewhat easier to handle outside of its frame. The tensioning frame clearly can fail and will need servicing, I don't use it heavily enough to have needed too yet. You do need a flat clear surface to (un)load it.Which is better.. difficult, I have them in different sizes but I could imagine the bigger your stencil the more you would appreciate a semi rigid frame, so while I would be tempted to say I prefer the Tecan, that might not be true if my Tecan was 23 or 29" in size.As expected the SP003 was tricky to setup and appeared to have something not quite right, either in the table lift or getting the top level. However before I could diagnose this mechanical issue the PLC stopped working and I had neither the time nor inclination to fix it. Could be a ribbon cable or something equally basic, could be the controller. I'd say the motor was quite a nice touch but nicer still would have been the vision addon as manually checking alignment over a 23" stencil inside this hulking metal frame was not ideal.

author: Reckless
author_rank: Frequent Contributor
timestamp: April 24, 2023, 08:33:51 am
content: How do you have them in different sizes? Can the SP-002ML take different sized stencil frames? It looks like its supposed to have 23". Id love to go down to 12" as my oven is 300mm.The tecan sounds nicer but as you say has to come from UK. Do you know if jlcpcb can supply vectorguard stencils? Id prefer to buy stencils from them if they are done correctly. How thick are they? Don't they also fit in a box?Good to know about the issue you had with sp003, the design looks very cumbersome. I also wish for vision but my SMT Tech says he uses his cell phone and magnifies alignment that way. I think I saw a camera lcd setup on amazon for $60.

author: SMTech
author_rank: Frequent Contributor
timestamp: April 24, 2023, 08:51:19 am
content: The Tecan was specifically purchased to stop using 17" Framed Alpha Stencils on a small and basic clamshell printer. To use it in the Essemtec I/you would need an adaptor frame, these are very common for 29" printers, less so for 23" however I think it's something you could make, I was going to but then failure struck.

author: SparkyStan
author_rank: Newbie
timestamp: April 26, 2023, 02:30:15 pm
content: Thought I'd add my anecdote of using our Essemtech SP002-VL over the last 6 months or so.I purchased ours used on Ebay so the squeegees were well used and required replacement. I was able to get new blades from Bluering stencils with their nano coating for around $65 CAD each. With my limited experience in printing so far, the new blades have worked much better than the original ones we received. I did have to make up a quick drawing for them to confirm the mounting dimensions.With regards to frames, we settled with the ASM/DEK 23x23" Vector guard system. This did not fit the printer as is so I made up some 3D printed adapters that live on our Vector guard frame with some large threaded knobs for fixing to the mounting cross beams. This has worked well thus far and I can change over stencils in a couple minutes. Pricing wise we're getting basic stencils for around $200 CAD and the nano coated stencils for $400 CAD from either Stentech or Bluering. I have purchased some framed stencils from PCBWay 23x23" for use with 3D printed adapters as well with decent success.For alignment we're using an HDMI microscope camera on a flexible arm and a spare monitor. I just quickly check a few features on the corners of the board and do minor adjustments as required. For larger run this had been tedious though and has put upgrading to a fully automatic printer higher on the list.One issue I'm still working on resolving are reliable printing of those 0402 sized DFN transistors. I've found that adjusting the vertical separation speed is sometimes required. I also have yet to finalize a solution for double sided printing. Our model is also hard to adjust the printing height on so I'm definitely looking for our final board fixture solution remove the need for that.