Neoprene Specs, Dimensioning & Tolerancing

[technobia]

Hello -

I am new to this site and hope I am posting in the correct place. I have a electro-mechanical drafting and design background in a manufacturing environment but have not worked in the field for a number of years.

I have a client who is trying to design sporting apparel that is made from neoprene in different thicknesses.
I am trying to develop a set of manufacturing drawings and material & silkscreen specs and have no idea what the standard approach should be.

Does anyone know of any standards or documentation guidelines or other resources that you could point me to for such kinds of product designs? I just obtained the ASME Y14.5M-1994 Dimensioning and Tolerancing standard and I am looking through it, but so far, I have not seen anything that directly relates the following items of concern:

1. Dimensioning and Tolerancing a pliable material.
2. How to dimension pattern pieces that have all kinds of complex curved lines
3. How items that are to be sewn or bonded should be articulated in an assembly drawing.
4. Defining silk screening with Plastisol

I would be grateful for some advice and suggestions.

Thanks -
Technobia

 

[MintJulep]

Good questions, as evidenced that no body has an answer on hand.

I'll take a stab to spur some further discussion.

1. Dimensioning and tolerancing a pliable material is really no different than a rigid material. The trick is, how do your inspect it?

2. If you can draw it, you can dimension it. Curves have radii, centers, arc lenghts and included angles. The same features you need to define it serve to dimension it.

3. I don't know, but I suspect that this might have somehting to do with why clothes turn themselves inside-out when you wash them.

4. Call Plastisol.

 

[notnats]

If the neoprene is to be cut using high pressure water jet, the cutter can probably be controlled from a DXF file, so it may not be necessary to make or dimension conventional patterns.

Whoever is to do the screen printing can guide you. I assume your question relates to positioning the garment for printing. They generally use a carousel with plywood supports for the garment, then the garment stays on the one support while the different colours are printed at each carousel station in rotation.

Jeff

 

[technobia]

Thanks for the input folks - it is helpful.

Good point I have no idea how this product can get inspected as on another site someone suggested to me that with patterns such as this, typically do not dimension them. Seems odd but OK. However, I would imagine there would still have to be some kind of assembly reference on the pattern pieces to locate them for assembly. This product is something someone designed from an existing product as a base that is being reverse engineered with modifications added into the design. I just want to male sure I articulate all that is required to get this thing documented for a quote and selecting a fab house.

Another suggestion I got for the silkscreen is to do it like you would for a PCB. That makes perfect sense and I have done that kind of work before. I would imagine that I just place the alignment targets somewhere outside the boundaries of the pattern.

 

[drawoh]

technobia,

Read Section 6.8 in ASME Y14.5M-1994. This covers how you fixture to datums of flexible objects.

The standard shows you ways to apply dimensions to complex curves. I recently used this to apply dimensions to ellipses, since I could not find a reference on them. Profile tolerances are your friend.

A number of members are claming they no longer use drawings at all. It appears to me that much of this involves the manufacture of complex parts that are hard to document with orthogonal drawings.

I have generated silkscreen directly out of SolidWorks. For high quality artworks, this is not a good idea, but SW is very close to being an adequate tool. Talk to your silkscreener and find out what they need from you.

JHG

 

[gwolf]

Technobia,

The manufacturing technique will govern how you define the shape and tolerances. For example:

If the neoprene is to be cut out using a computer controled machine then supply 2D CAD drawings, usually in DXF format for this type of work.

If the neoprene is to be cut by hand then a full-size paper lofting will be required.

etc.

gwolf.

 

[notnats]

What kind of sporting apparel is made to such close tolerances?

Jeff

 

[technobia]

Jeff -

I can't really say because of a non-disclosure agreement. I will be able to some time down the road. I am not sure how tight the tolerances should be and that is part of my deli mea. I am still not sure about the manufacturing processes to determin that. I defiantly have more research to do. As MintJulep said. How would we inspect it?

Thanks -

 

[MadMango]

I'm invisioning some form of wetsuit or "sport jacket" for equipment. I think if a wetsuit, manufacturing methods might be similar to normal articles of clothing, meaning you might want to investigate pattern makers and how clothing is laid out.

[green]"I think there is a world market for maybe five computers."[/green]
Thomas Watson, chairman of IBM, 1943.
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[diamondjim]

Is this just one half of the pattern
and is the other half bonded or
glued to the other half?
I cannot believe that and error of
plus or minus 1/8 inch would make
any great difference in a stretchable
product. We have no idea of the
size of units that you are working
with.

 

[technobia]

All I have to work with is a pattern drawing that has no reverences to size or dimensioning or tolerancing. All I can do is a crude distance measurement in in AutoCAD or try to dimension the pattern in some locations to get the actual size to try an figure this out.

I think someone reverse engineered a similar item and traced it to get the DXF patter files I have. There are several sizes and I have to look at the ratio between them still. It is very clear to me that I should look into what MadMango suggested to better determine the approach to this as well as finding a potential manufacturer to get a better handle on their processes and requirements.

I so appreciate this forum and the input from everyone. It is VERY helpful! THANKS!

 

[MadMango]

I have 2 wetsuits, both are constructed in similar methods. Both have multiple panels (or sections) and are made of mutiple thicknesses (2-3-4mm and 5-6-7mm) joined with "compression glueing" and sewn. You might want to visit a few wetsuit websites as they tend to describe construction methods. I would think a general note would suffice on the assembly drawings.

In some areas, I can see where +/-.125 tolerance would be too great, but I would think a +/-.063 would be plenty.

I would contact a silk screening vendor to find one that has experience with Plastisol or similar materials and ask how they like it specified on drawings. RAL/Pantone color codes, applied thickness, etc, etc.

I also think that the "assembly drawing" is refered to as a "pattern sheet" and is probably more akin to a weldment drawing than an exploded assembly drawing. Meaning that arrows and callouts are used to define thread weight, thread pitch, thread style, etc, etc.

[green]"I think there is a world market for maybe five computers."[/green]
Thomas Watson, chairman of IBM, 1943.
Have you read faq731-376 to make the best use of Eng-Tips Forums?