Homebrew PCBs

Hi All,

Even though this isn't directly a PCB-related topic, I figured it
applies enough and the information would be valuable to most of us.  I
make a lot of wiring harnesses, sometimes with wire of the same color.
 I've been thinking of various ways to print directly on the wires. 
The wires I work with are PE/PVC/silicone insulated, 20-24ga. stranded
copper wires.  Here are a few ideas I've had:

*Secure a professional hot stamp/ink jet wire marking machine: very
costly and probably overkill.
*Devise a small machine based on rubber stamps.  Rubber stamps are
cheap, but can they print small enough text?
*Devise a different small machine based on stencils.  Many of us,
myself included, use mylar laser-cut stencils for SMT PCB's.  I know
they can be cut with enough resolution, so why not just make a small
jig to hold the wire while a pad wipes ink through the stencil?  Not
as cheap as the stamps, but not bad... especially if you panelize.
*Build a DIY ink-jet printer.  Parallax used to sell a serial ink-jet
kit for under $100.  I'm sure I could scrounge the parts and a surplus
controller board from somewhere... but can it print small enough?  

Any other ideas?  Do any of you have experience with this? 

I've seen the thermal label "wire" printers that print to adhesive
labels, but they're too time consuming.  If any of these methods work,
I'm sure I could automate the process to a degree.  My goal is to
easily mark bundles of 20-40 wires (each with different labels), about
12' long marked every 3-4". 

Thanks!

-PS

Inkjet printers for wire marking are not the same as the typical
desktop inkjet printer. They use a solvent-based ink that dries
essentially instantly. The printhead fires a continuous stream of ink
drops which are  deflected by electrically charged plates, with the
unused ink drops being caught by a vacuum system and reused. The
machines are complicated and need a good deal of maintenance.
Consumables such as ink, make-up liquid to replace evaporated solvent
from the ink, cleaning solvent, filters, etc. are expensive. I don't
think this is a practical do-it-yourself project, and the commercial
equipment only makes sense if you're running a high-volume operation.

I think your best bet is to find a wire processing or harness-building
company that has not been driven out of business by imports from the
Far East and have them mark spools of wire for you. Try looking
through the membership list of the Wiring Harness Manufacturers'
Association to see if there's a company near you that can do the job.

http://www.whma.org/Membership/RegularMembershipRoster.aspx

In one of my past job I was involved in wires manufacturing.

For my experience, the easiest and fastest solution is rubber roll
used for print transfer.
Very good imprinting up to 0,5 mm (or less).

Remember that Silicones need different ink from PVC which is different from PE.
Same probably apply for Ink Jet.

And, if you need a durable and good looking marking, you need some
sort of corona effect (this apply to some sort of PE,   and all PFA,
MFA ecc. (fluoro derivated).

Hope this can help you,

Simone

2008/5/15 tgr8883 <symansky@...>:

> Hi All,
>
> Even though this isn't directly a PCB-related topic, I figured it
> applies enough and the information would be valuable to most of us. I
> make a lot of wiring harnesses, sometimes with wire of the same color.
> I've been thinking of various ways to print directly on the wires.
> The wires I work with are PE/PVC/silicone insulated, 20-24ga. stranded
> copper wires. Here are a few ideas I've had:
>
> *Secure a professional hot stamp/ink jet wire marking machine: very
> costly and probably overkill.
> *Devise a small machine based on rubber stamps. Rubber stamps are
> cheap, but can they print small enough text?
> *Devise a different small machine based on stencils. Many of us,
> myself included, use mylar laser-cut stencils for SMT PCB's. I know
> they can be cut with enough resolution, so why not just make a small
> jig to hold the wire while a pad wipes ink through the stencil? Not
> as cheap as the stamps, but not bad... especially if you panelize.
> *Build a DIY ink-jet printer. Parallax used to sell a serial ink-jet
> kit for under $100. I'm sure I could scrounge the parts and a surplus
> controller board from somewhere... but can it print small enough?
>
> Any other ideas? Do any of you have experience with this?
>
> I've seen the thermal label "wire" printers that print to adhesive
> labels, but they're too time consuming. If any of these methods work,
> I'm sure I could automate the process to a degree. My goal is to
> easily mark bundles of 20-40 wires (each with different labels), about
> 12' long marked every 3-4".
>
> Thanks!
>
> -PS
>
>

Hi,

 

I figured there must be major differences between industrial wire marking
inkjet printers and your average DeskJet, but I was surprised at the
resolution the Parallax kit could achieve.  Furthermore, there are a variety
of quick-drying, permanent inks available for use in inkjet printer
cartridges.  In any case, it was just an idea.  inkjet printing wouldn't be
my first choice regardless.

 

Thanks for the link to the WHMA, though!  I was unaware such an organization
existed.

 

Simone,

 

Can you explain the rubber roll process a little more?  Is it a type of
flexography?  It sounds to me like it uses rubber or silicone dies to stamp
the labels directly to the wire.  I was beginning to lean in this direction
after thinking about it.  My plan was to lay out the design in ACAD, then
have a rubber stamp manufacturer create the die.  Additionally, I've found a
few permanent stamping inks that supposedly mark non-porous materials like
glass, metals and plastics really well.  \

 

Thanks!

 

-PS

 



[Non-text portions of this message have been removed]

2008/5/20 Paul Symansky <symansky@...>:
>
> Simone,
>
> Can you explain the rubber roll process a little more? Is it a type of
> flexography? It sounds to me like it uses rubber or silicone dies to stamp
> the labels directly to the wire. I was beginning to lean in this direction
> after thinking about it. My plan was to lay out the design in ACAD, then
> have a rubber stamp manufacturer create the die. Additionally, I've found a
> few permanent stamping inks that supposedly mark non-porous materials like
> glass, metals and plastics really well. \
>

Actually all the roll process are based upon metal engraved rolls.
You can find a technical data sheet of such rolls at

http://www.rsd-technik.de/data_sheets/Data_sheet_wheels.pdf

There are two basic way of roll print: direct print and offset print.

Direct print uses engraved metal rolls; can achieve very high speed
(up to 1500 m/min). Roller printer are expensive (almost as inkjet),
as they have multiple print head, ink refrigeration, automatic density
controll. Roller head are quite complex as they are rotating at the
same speed of the cable to be printed by a motor.

Offset print use a porous rubber roller. A metal roller (always
engraved) is transferring the ink from a container to the rubber
roller. On the rubber roller there is the formation of the "image" to
be transferred to the wire/cable.
Quality is superior, apparatus cheaper and very low speed (up to 80 m/min).

We were using such a sistem for marking a green line on very thin wire
(28 AWG if I remember), were we did not have secondary extruders for
making a bi color insulation.

If you really need inkjet printing, I think that you can find some old
used industrial printer somewhere at bargain price (have sold some old
units at about 1000 euro two years ago).

Ciao,

Simone