×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Reference on plastic parts manufacturing

Reference on plastic parts manufacturing

Reference on plastic parts manufacturing

(OP)
Can anyone suggest a good technical reference on plastic part manufacturing including materials selection and various manufacturing methods? I need to know much more about plastic part design and manufacturing. Thanks in advance for your suggestions.

Howard Bruce Jackson
Senior Mechanical Design Engineer

Tunalover

RE: Reference on plastic parts manufacturing

SPI publishes a huge volume of material.
Most of it is fairly pricey, and there's certainly useful stuff in there somewhere. The volume of material actually makes it hard to find what you want.

For free, you can inquire of every plastic resin manufacturer you can find. They are all extremely interested in getting you up to speed, and using their products with unbounded success. To that end, they provide excellent engineering and/or design handbooks, nowadays as pdf files, but you may be able to find printed material to fill a bookshelf or six.

Of course, having material organized by resin or by brand makes it harder to select among the various resins and brands, one task for which the SPI material may be more useful.

Also, if your outfit is already dealing with plastic fabricators or molders, it would be a good idea to get acquainted with them. Spend a day with each, learning what they do, how they do it, and see some of their challenges firsthand.

If you are really going at this cold, do some destructive examination and comparative anatomy on things like disposable razors and toothpaste pumps. Then try to design something yourself. Maybe like a piece of a carburetor. Most molders are hot rodders, so will understand carburetors for a few more years. Take your detailed design for a carburetor part (or whatever) to a couple of molders, and take notes about what they say after they stop laughing.



Mike Halloran
Pembroke Pines, FL, USA

RE: Reference on plastic parts manufacturing

(OP)
Thanks Mike!

Tunalover

RE: Reference on plastic parts manufacturing

Like Mike implies some vendors have design guides on their websites etc.

E.g. our RIM vendor has this http://www.premoldcorp.com/design-guide-download/

These guys have design guides on a number of rapid prototyping processes aw well as 'injection molding' http://www.solidconcepts.com/resources/design-guid...

Posting guidelines FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm? (probably not aimed specifically at you)
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?

RE: Reference on plastic parts manufacturing

(OP)
Thanks Kenat. I know there always is the prerogative of getting with the plastic fabricators. That is always the BEST source of information but what I'm looking for are general design guidelines for various fabrication methods that would apply to ALL fabricators. Maybe a textbook or handbook of some kind...

Tunalover

RE: Reference on plastic parts manufacturing

The rules don't apply to all molders.

My friend Siggy, now sadly not available for consultation, specialized in low volume injection molding, using molds mostly made of aluminum plates, with no draft, manually removable pins to make holes, and steel for the odd fine detail. His molding machine was simple, and part ejection involved disassembling the mold from around the part. ... with an impact wrench. ... in a carefully choreographed dance of assemble, clamp the mold in the machine, inject, removed the mold to the bench, disassemble, repeat, in order to provide part consistency.

Siggy put a red mark on every feature that I had carefully provided on the first drawing I sent him. I had to remove the draft and the clever half holes and such.

My point is that in injection molding especially, you have to be a partner with your supplier in order to get the results you want. Many, maybe most, molders are self-taught, clever, arrogant in a good way, and busy enough to not really need your business. They each do everything in their own way, so molds don't really interchange among molders, even though you technically own them and could move them.
If a Supply Chain Manager gets involved in the procurement of molded parts, you might as well close the doors, because you will shortly be out of business.

So, I repeat, if your outfit is now doing business with molders, you need to personally visit them and get acquainted.

Mike Halloran
Pembroke Pines, FL, USA

RE: Reference on plastic parts manufacturing

(OP)
Mike,
I always partner with the fabricators. But I am also generally not empowered to choose suppliers. I am generally told to design parts loosely enough that many molders could deliver them. However, there are always molders that are favored for the time being and those are the ones I work with to review designs for manufacturability. Sometimes I send a print out to more than one molder for review and comment.

Tunalover

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources