Need a Permaneant Marking on Delrin 5

[stlbballer33]

I have two objects made of black delrin that need to be alligned properly in the field. I would like to put some sort of white or colored marking on each object that would show that the objects are alligned properly. I'm having trouble finding a way to make a permaneant mark (this is a medical device so it will be cleaned thoroughly between uses). Any suggestions or advice?

 

[CorBlimeyLimey]

Can you create an actual alignment feature instead? (tabs, indents, grooves, dots, etc)

 

[byrdj]

a scribed line ?

 

[stlbballer33]

That's was going to be the next step...just put matching grooves in - however since the material is black I was hoping for a way which would be easier to see...

 

[KENAT]

Any way you can insert a little 'key' or something of white (beige) delrin?

Cost wise may not be possible and could be a trap for germs but it's an idea.

I'd say fill the scribe line with some marking medium but that takes you back to step 1.

KENAT, probably the least qualified checker you'll ever meet...

 

[handleman]

With it being a medical device, I doubt much of any type of surface marking would hold up. Perhaps a dab of some colored epoxy, possibly smeared into a small groove or scribe line, would stay for a while.

 

[Heckler]

What about laser marking? We laser mark a lot of plastics.

Heckler
Sr. Mechanical Engineer
SWx 2007 SP 4.0 & Pro/E 2001
o
_`\(,_
(_)/ (_)

"Avoid the base hypocrisy of condemning in one man what you pass over in silence when committed by another." -- Theodore Roosevelt

 

[KENAT]

Does the laser marking change the color? Would it be visible on black. We laser engrave some stuff but you'd still have the problem of picking it out on background of same color, especially black.

KENAT, probably the least qualified checker you'll ever meet...

 

[Heckler]

It lightly etches the surface but it depends on the material and the laser engraver. We use laser impressions in Sunnyvale, CA

http://www.laserimpressions.com/medical.html

Heckler
Sr. Mechanical Engineer
SWx 2007 SP 4.0 & Pro/E 2001
o
_`\(,_
(_)/ (_)

"Avoid the base hypocrisy of condemning in one man what you pass over in silence when committed by another." -- Theodore Roosevelt

 

[stlbballer33]

The laser etching is not a bad idea - although I feel like it would unnecessarily expensive. Another idea I had was to put a label or clear sticker of some sort onto the objects with just a yellow line (any ideas where to find such a sticker?).

 

[Heckler]

You will have problems with adhesion.....been there done that.....laser marking is very professional and not that pricey.

Heckler
Sr. Mechanical Engineer
SWx 2007 SP 4.0 & Pro/E 2001
o
_`\(,_
(_)/ (_)

"Avoid the base hypocrisy of condemning in one man what you pass over in silence when committed by another." -- Theodore Roosevelt

 

[CorBlimeyLimey]

If the main material is shiny black, create a matte finish on the alignment mark ... or vice versa. It is surprising how black on black marking can stand out ... especially in good lighting such as an operating theatre.

 

[GregLocock]

3M have been very helpful in the past in providing permanent labelling solutions.

I'm not convinced that anything will really survive autoclaving and scrubbing, repeatedly, but they'd be my first port of call.



Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[MintJulep]

Some grades of delrin are moldable.

I wonder if you could drill a hole in your black part, and have it filled with a contrasting color molten delrin, resulting in a fused in spot of different color.

 

[MikeHalloran]

Mold it from _white_ Delrin.
Then boil it in Rit dye.
Then laser engrave it.


( For about 20..30 minutes, the dye doesn't affect the Delrin, at all. Then, just when you begin to wonder if you followed the directions right, it proceeds from a light to a dark shade in just a few minutes. )



Mike Halloran
Pembroke Pines, FL, USA

 

[Pud]

POM is available with pigmentation which can be colour changed by laser - the black base gives a light green mark - pale colours which go darker are obviously better. The sample black I have seen (years ago) was quite acceptable for say, an id number or other functional marking.

I think Ticona make the stuff, but Du Pont may also do it:

http://www.ticona.com/redesign/index/tech/part_finishing/laser_marking.htm

Cheers


Harry

 

[tygerdawg]

I think you should follow Heckler's advice. For years I did laser marking on black Nylon 6 objects that produced bright, white, high contrast indelible marks.

There are plenty of contract laser marking shops. Laser marking doesn't cost much per piece, especially if you have the volume to amortize the setup charge.

As a test, you can contact companies that sell laser markers, ask their Applications Engineering Department about marking Delrin, and they typically will do free samples for you. This will lead you to the required process parameters of CO2 versus Nd:YAG lasers (or even the more exotic laser types), power levels, pulse rate requirements, traverse speed requirements, etc.

TygerDawg
Blue Technik LLC
Advanced Robotics & Automation Engineering

http://www.bluetechnik.com

 

[Pud]

As a cheaper capital cost option, you could hot foil print. That's quite permanent with the correct foils.


Cheers


Harry

 

[fcsuper]

Heckler,

I drove by those laser guys almost every day on my commute to work.



Matt
CAD Engineer/ECN Analyst
Silicon Valley, CA
sw.fcsuper.com
Co-moderator of Solidworks Yahoo! Group

 

[jistre]

I'm with CorBlimeyLimey on this one. I've found that alignment features as opposed to markings are much more foolproof. In the past, I've tried markings, tabs, etc. and the best luck I've had for proper alignment in tricky spots on molded parts was a visual feature that indicated proper alignment, then mating features on the two parts to seat them.

On one project, it was simple as molding a hole into the parts in question that only aligned upon proper assembly. Not only did it provide a visual clue as to how to put the parts together, but it was an excellent quality assurance feature. If you couldn't see through the hole in the assembly, you knew you'd put it together wrong.