Author Topic: Stencilling (split from feeder discussion)  (Read 25210 times)

Mike

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Stencilling (split from feeder discussion)
« on: April 07, 2011, 11:12:38 PM »
I was mainly thinking it's one thing for you to create this machine and sell it using whatever model, but quite another for david to cut down his and follow you in.

Do you have any plans for the rest of the process?  Manual stencil printers are quite expensive and not really that clever. The same could be said for ovens especially batch ones which I guess is what one would partner this with.
I think stencil printing is something that someone needs to do a good job of. It's hardly rocket science, just needs careful design for low-cost manufacture. Absolutely must be able to use unframed stencils of any size, including plastic ones.
One neat idea I saw was that instead of fine-adjust screws, you use magnetic PCB holders with a thin carbon-fibre sheet between them and the baseplate, allowing adjustment by pulling the sheet from the side.

The Eurocircuits one[/quote] looks pretty good but expensive

Ovens are a lower priority as toaster ovens are perfectly useable for soldering in a budget-limited environment.

fcb

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Stencilling (split from feeder discussion)
« Reply #1 on: April 09, 2011, 01:45:44 PM »
What a sigh of relief that must have been.
The ability to use "elemental?" or freebie stencils I would guess is most easily solved by making a standardish frame  based clamping and tensioning system to hold them. That would leave the base/table/whatever flexible enough to hold some common frame sizes. I believe some of the prototype pcb shops now do cut cost reusable frame systems of some form. Maybe that bit would then be an optional extra.

The Elektor one seems a sensible enough design but I kinda want the top half and it needs to be bigger, 450mm both ways would be better.

Stencilling.  It's something I put time into awhile back (again at the time I couldn't find a low-cost unit), it's also part of the trio we would like to produce long-term (fortuatley I have a large 7-zone oven that has been 100% reliable and cost £400 on ebay a few years back, so I haven't built a toaster-unit yet).

Mike made some interesting comments on biggest headache with stencil printer design the X/Y/Theta mechanism.  I would hate to do low volume production with the Elektor unit.  Likewise I would worry about the lack of adjustable fine-alignment bit on the Eurocircuits machine.

I would hope Mike could split the last few posts of an create a 'stencil printer' thread.

As far as toaster ovens - those T962's on ebay look good value, any experience with them?


Gopher

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Re: Stencilling (split from feeder discussion)
« Reply #2 on: April 09, 2011, 06:16:01 PM »
http://www.mekko.co.uk/about.html we have that one at the bottom..., I've switched from the rubber blade pictured to a stainless one fitted to the same holder with the help of a 9" strip of wood.
Its effective enough, especially now we have a self tensioning frame, but I see the pcb mount systems other systems have and get jealous, old scraps of pcb and sellotape just seems so crude in comparison, and double sided means I have to rummage around for something to cut up or drill holes in.

davidc

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Re: Stencilling (split from feeder discussion)
« Reply #3 on: April 10, 2011, 10:45:00 PM »
T962....   ::)  you are kidding. There is so much good kit out there..but if its on Ebay it must be good  :D

Have spent a lot of time recently looking for a good supplier of Printers and Ovens… Still looking…but close on the printer front now.

Gopher

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Re: Stencilling (split from feeder discussion)
« Reply #4 on: April 12, 2011, 11:48:39 PM »
Hmm apparently I walked right past the eurocircuits one today, have the naff PCB bookmark and failed to notice they had it on the stand.

SteveW

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Re: Stencilling (split from feeder discussion)
« Reply #5 on: July 21, 2011, 03:31:10 PM »
Crumbs, looks like there really is a demand (and maybe some margin to be made on) manual stencil printers.
http://search.ebay.co.uk/220813898605 - a baby OKI SSP-75A SMD - 21 bids from 9 bidders, £487.77

Anyone here?
(I've got one just like it. It's Ok, but I wish it was just a tiny bit bigger, had some tensioning, and support for doing the second side.)

Steve


Mike

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Re: Stencilling (split from feeder discussion)
« Reply #6 on: July 21, 2011, 05:44:31 PM »
I was thinking the other day, one reason stencil printers are expensive is they are made of big lumps of metal. I wonder if you could make a decently solid  printer from wood...
Long-term stability issues due to moisture shouldn't be an issue as it only needs to be stable between adjustment and printing, and I imagine there would be some clever ways to keep things parallel.

 

phonoplug

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Re: Stencilling (split from feeder discussion)
« Reply #7 on: July 27, 2011, 01:16:58 PM »
I'd reckon the cost is due to the low volumes of manufacture and the processing of materials, not the cost of materials themselves.

Not sure you could make it square enough from wood, certainly not long term, so that it can hold the stencil prefectly parallel to the PCB surface, while under tension.

Just my 2p worth though.

Gopher

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Re: Stencilling (split from feeder discussion)
« Reply #8 on: July 27, 2011, 03:13:21 PM »
Volume and the fact perhaps that the resellers more often deal with big ticket items so selling something small and cheap is disproportionately expensive.
Given that 23" manual printers before including the frame are €3k++ there seems to be plenty of margin in there for someone to undercut it if they then took modern, lower cost routes to market by selling it on ebay or direct from their website and pushing it via word of mouth, Google adwords, and sneaky use of bulletin boards.
That said what does one consider a sensible or "Low" price? Just the self tensioning frame I use was ~£800 and IMHO worth every bit of it.

phonoplug

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Re: Stencilling (split from feeder discussion)
« Reply #9 on: July 27, 2011, 03:22:38 PM »
I recently paid £1100 for a printer that will accept stencils upto A4 size. Doesn't need any special holes in the stencil and is adjustable meaning I can use stencils from various sources at pretty low prices. With the addition of some aluminium tooling plate to sit the PCBs on rather than the naff standoffs you have to use normally, it does a really good job. The PCBs I pasted in it recently are in A4 size panels, have QFP48s with 0.5mm pitch in opposite corners of the panel and I had no problems whatsoever with alignment, repeatability and smudging. Worth every penny.

Mike

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Re: Stencilling (split from feeder discussion)
« Reply #10 on: July 27, 2011, 03:28:07 PM »
I recently paid £1100 for a printer that will accept stencils upto A4 size. Doesn't need any special holes in the stencil and is adjustable meaning I can use stencils from various sources at pretty low prices. With the addition of some aluminium tooling plate to sit the PCBs on rather than the naff standoffs you have to use normally, it does a really good job. The PCBs I pasted in it recently are in A4 size panels, have QFP48s with 0.5mm pitch in opposite corners of the panel and I had no problems whatsoever with alignment, repeatability and smudging. Worth every penny.
Make/model?

phonoplug

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Re: Stencilling (split from feeder discussion)
« Reply #11 on: July 27, 2011, 03:42:42 PM »
Its a Techno SD 300. Saw it on Blundell's stand at Southern manufacturing show earlier this year. Left a card with them for them to send me a quote and they never bothered. I emailed them a month or so later for a price, but it was cheaper (by about £150) buying from the Danish distributor who was really friendly. Blundell weren't interested in negotiation so I got it from Danish guys, http://www.printtec.nl/ (they speak good English!)

Printer is here:

http://www.technoprint-smt.nl/sp-sd300.htm

Gopher

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Re: Stencilling (split from feeder discussion)
« Reply #12 on: July 27, 2011, 04:02:01 PM »
http://www.stencilsunlimited.com/stencil_printers.php here's a whole page of them including that one in USD, that one looks pretty good to me, especially for the low volume freebie stencil sort of thing.