Problem:

 

I am looking to get some prototypes made for some glassware designs. I have 3D files for the designs and am wondering if anyone has any experience making realistic models from such CAD files (STL etc). In the past, we have had a model maker create acrylic bottle shapes from CAD files (to simulate glass), but those designs were all symmetrical and some of these designs may not be. Is it possible to do accurate, one off castings in glass-like material? Anyone have experience making glass-like models?

 

Solutions:

 

Glass Lab Method

 

From Dave Duff: When I worked at Lockheed years ago, I once visited their labs in Palo Alto and saw some amazing lab glassware. Turned out that they contracted it out to a guy who would assemble custom lab glassware from standard shapes and blow custom parts as needed. There may be glass blowers who can create what you need in glass. Such individuals are probably hard to find. The other option that comes to mind is to have your piece CNC machined (in assemble-able pieces if need be) in polycarbonate, solvent glued together, and then vapor polished.

 

Connecticut Plastics could probably do this for you.

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Water Clear SLA Method

 

From Christine McElhany: We've also used the water clear SLA with success. But you need to be a stickler to the vendor to attend carefully to he finishing step, and give it a nice thick clear coat finish. If they half-ass the finishing step the parts can still come back hazy and with distorted clarity just because of the surface. The thick clear coat will make the parts glossy and give them visual depth, as well as help cover up any surface imperfections, but will also throw your part tolerances way out, which hopefully won't matter for an aesthetic build. The parts will have a very slight yellow tint which hasn't bothered our ID eyes.

 

We've used SolidConcepts successfully.

Never tried Metropolis Design but maybe we will.

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From Mike Lin: I might recommend the following process to get water-clear, glass-like prototypes:

 

CAD model to produce a high resolution SLA

Hand-work to improve surface finish to remove the "stepped layers" from the SLA process

Casting an RTV mold around the SLA model

Casting water-clear resin, epoxy or urethane in the RTV mold

Finally, hand finishing/ buffing/ polishing

 

I highly recommend Protogenic

http://www.protogenic.com/

"Arlen Juels" <Arlen@protogenic.com> 

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From Dave Franchino: Our shop has done some remarkable work getting glass-like results from the water-clear SLA’s with a lot of attention to prep as you might imagine. I asked our shop director for the technique – nothing surprising but it’s repeated below. If you have specific questions feel free to call Dan (see below) as his team is pretty adept at this.

 

1) Build part via SLA in a transparent resin, we typically specify Accura 60 for “clear” parts.

2) Meticulously sand the SLA part inside (if possible) and out with progressively finer grits of abrasive paper removing all build layer lines. The finer the surface preparation, the more effective the part transparency will be. Typically, we sand to a 400 grit for a particularly nice appearance.

3) Apply a high gloss clearcoat (this is the most important step). We use a catalyzed high gloss clear urethane intended for automotive refinishing. With limited spraying capabilities and reasonable expectations, suitable results might be achieved with something as basic as clear gloss Krylon from an aerosol can.

 

Dave Franchino | president + principal | 608-316-8440

Design Concepts, Inc.

5301 Buttonwood Dr. | Madison, WI 53718

www.design-concepts.com

 

Dan Bullis | chief operating officer + principal | 608-316-8447

Design Concepts, Inc.

5301 Buttonwood Dr. | Madison, WI 53718

www.design-concepts.com

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Clear Polyjet Printing

 

From Mario Madrigal: In response to the project there are some options to pursue that I can think of right now:

 

1) Clear Polyjet (3D printing): layers in 16 microns, but not incredibly functional. This would need to be polished and clear coated and will look like glass but it has a slight amber tinge to it which may take away from the glass-like aesthetic. I have some attached pictures. Also, you should note that after some time the parts may warp especially if exposed to heat and moisture.

2) Urethane Casting: I will try to find some optically clear parts for this process, it might be more costly (depending on the quantities) but you will get completely functional parts. The problem is that the optically clear urethane is finicky to deal with in terms of its curing time (so it would not be advantageous to rush that method if you had tight deadlines).

3) Machining and Polishing Acrylic. Might be difficult/costly to achieve organic shapes and solid acrylic tends to be quite expensive.

 

If I had to suggest the best method it would be polyjet because it would be cheaper than casting or machining if you were looking at various different designs as opposed to several quantities of one design. Like I mentioned earlier, the problem would be the slight amber tinge to the part.

 

Mario Madrigal

Account Manager

ProtoPulsion, Inc.

www.ProtoPulsion.com

mario@protopulsion.com

650.369.5335 x16 (office)

650.649.1898 (fax)

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SLA Master Mold with Clear Acrylic Resin Method

 

From Eliot Sather: If the "water clear" SLA is not clear or smooth enough for your needs you could make regular SLA masters and make a two part RTV mold using the SLA part as a master. You could then use clear acrylic or another resin to cast your final parts. The trick would be finishing the master patterns very well before making the mold so that they were very smooth (layers of primer and fine sanding), then the final parts would be smooth and clear. The other advantage of this technique is that if you need more than one model you would likely save some money. This is an older model making method but I think lots of places still do it, such as

 

Phillip Roberts in Palo Alto

Prototype Plus in Menlo Park

Solid Concepts, down in Valencia 

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From Jamie Page: RP technologies have evolved significantly in the last few years. There are now several other options in addition to the generally well known technologies like SLA and SLS. The process you want will greatly depend upon the specific surface finish you are looking for. If you don't need a gloss finish and you can tolerate hand finishing (sanding with very fine sandpaper and then bead blasting) you could go with a high resolution SLA. If you need a gloss finish (more like glass), you might consider polyjet. Polyjet is a process that UV cures a resin that is essentially inkjetted in very very thin layers and the possible resolution and surface finish have improved greatly recently. The process can result in a gloss finish with imperceptible or barely perceptible layers, unlike SLA where layers are generally visible before hand finishing and finish is generally matte. There are several good vendors for polyjet including RedEye.

 

There are also other processes available. I would suggest discussing your requirements for surface finish and optical clarity with a good vendor as they will have the most up to date info on the latest materials.

 

If you really need results that look just like glass and can pay a little more, you could use RP + hand finishing + careful gloss paint as a master for a silicone mold + resin casting. This will be about 10x the cost of just the RP, but results are possible that look just like glass.

 

My thoughts on the water clear resin that was suggested will get you reasonable results if you can accept something that is close but not quite like glass (slightly cloudy, a little grey color, small but visible layers). Also you might ask about options for dying RPs post build if you need color.

 

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Referral Summary:

Glass Lab Method

 

1) Farlow’s Scientific Glassblowing, Inc.

Koryn Lakeman

koryn@farlowsci.com

Phone – (800) 474-5513

Fax – (530) 477-9241

 

2) Connecticut Plastics

 

3) R&D in Oakland

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Water Clear SLA and Other Methods

 

1) ProtoPulsion, Inc.

www.ProtoPulsion.com

Mario Madrigal

mario@protopulsion.com

650.369.5335 x16 (office)

650.649.1898 (fax)

 

2) Design Concepts, Inc.

Dan Bullis | chief operating officer + principal | 608-316-8447

Design Concepts, Inc.

5301 Buttonwood Dr. | Madison, WI 53718

www.design-concepts.com

 

3) Prototype Plus in Menlo Park

 

4) Solid Concepts, down in Valencia

 

5) Phillip Roberts in Palo Alto

 

6) Metropolis Design in Salt Lake

 

7) Protogenic: http://www.protogenic.com/

"Arlen Juels" <Arlen@protogenic.com>

 

8) Quickparts.com

 

9) Sputnik models: http://www.sputnikmodels.com/

 

10) RedEye