3D Printed Replacement Part Marketplace

[atowler]

I'm looking into starting an online marketplace to connect people who are looking for replacement parts (automotive and otherwise) with people who can design and 3D print parts. Sure, the parts won't be original, but some parts are nearly impossible to find or just make more financial sense to have printed. With modern 3D printable plastics you can print things that will be exposed to ultraviolet radiation from the sun and under hood temperatures, so it wouldn't be limited to just aesthetic components. Here's how I'm thinking it would work:

As a buyer seeking to have a part designed you would set a bounty for how much you are willing to spend. A designer then can accept the bounty, design the part, then send it to you. If a part has already been designed then you only have to pay the fee for having it printed since the design work was already done. I'm still working out the details so it's subject to change. I'm really just trying to get a feel for if this is even something that is wanted before I go about making it. Thanks for your feedback!

[Mike Mahar]

If there REO the first parts I'll design them for free!

[Gary_Ash]

For most of the pre-war cars, there are a few parts which could be replaced directly by 3D printed functional plastic parts.  Generally, a 3D printed part can be used to serve as a pattern for casting in aluminum or silicon bronze.  However, the casting may need grinding, sanding, machining, and plating to make it functional and the right color.  The CAD designer has to understand all the processes to be implemented in order to incorporate draft angles for sand casting, shrinkage allowances, and machining allowances.  Direct-to-metal 3D printing is coming along, but the parts still require machining and finishing.  That said, there are some 3D printed plastic parts that can be used as is, such as knobs, electrical insulators, escutcheon plates, etc.  Reproducing a part when there is at least an original 2D drawing available isn't too difficult a task.  However, creating a usable 3D model from photos and a few measurements may not yield a part that looks exactly the same and fits.  So, who takes the responsibility for getting everything right and paying for the efforts that are not close enough?  I've made a bunch of parts using 3D printing but don't really want to spend my time offering design and fabrication services to all comers.  I hope you find some capable people who are willing to do that.

 

Here are some parts I've made using 3D printing on a $200 Creality Ender 3 printer and TurboCAD Pro software.

 

3D printed master of carb linkage arm.

 

Rough castings made by investment casting in silicon bronze from wax copies of master part (lower right).

 

Castings after drilling, slot sawing, and tapping.

 

Arms and links after zinc chromate plating.

 

Low tension terminal for Delco-Remy 662M distributor.  Brass contact machined and pressed in to black ABS plastic.  [Computer-rendered image]

 

High tension terminal for Delco-Remy 662M distributor cap with metal contact machined and pressed in.  Black ABS plastic used for printing.

 

Translucent speedometer face 3D printed, sanded, painted, and reproduction decal applied.

 

Fuel filler with cap, about 4" diameter, with 3D printed PLA plastic pattern and silicon bronze raw castings from "lost PLA" investment casting process.

 

Fuel filler assembly after machining, polishing, and chrome plating.  The Indy car model was also 3D printed on the Creality Ender 3 printer over a 60 hour run.

[edinmass]

Gary is 100 percent correct with his statements that it’s not easy or a direct path to a good part using 3D printing............expensive ultra modern printers give a better finish to the pattern than what was available just a few years ago. But most cars values don’t justify all the time and expense to manufacture parts and inventory them. Many people think a later scanner will scan a part, and the printer will make what you need. It’s no where close to that. 

[carbking]

While I have never used 3D printing, it seems to be a tool to maybe simplify production of a part.

 

BUT

 

The financial successful production of a part depends in a large part on demand.

 

As an example: I have a set of new old stock air valve springs for the Packard (Detroit Lubricator) carburetor used on a decade of Packards up to spring 1929. 40 years ago, I sent the samples to a "Mom n Pop" spring winding company and had 100 sets made to put in the rebuilding kits for those Packard carbs. It took 38 years to go through 100 sets. Now the "Mom and Pop" company has been inherited by the children who now want a 2500 piece minimum. Even if I could still get the 100 minimum, I would not redo these parts at my age.

 

To the OP - I wish you luck; however keep in mind the comments by others about quality. Somewhere the buck must stop. If one does not care about quality, "stuff" can easily be made in a country far away. And there are some who look only at the bottom line.

 

Jon.

[Terry Harper]

This topic comes up often. As Gary stated its not simply modeling the part - there is a lot more to it depending upon the expected outcome which needs to be defined. For instance is the client satisfied with a rough casting versus a fully machined part? there is a huge difference between the two.

 

Same with using a 3D printed part as THE finished component or using it as a foundry pattern or a rough 3D printed part that requires machining. In all cases expectations need to be defined.

 

All of this greatly impacts the CAD designer and can impact greatly the cost. For instance if the expectation is a foundry pattern than as the designer I have to figure out the part lines, scale the component appropriately to account for shrinkage, add draft and machining allowance. Then whether its a 3D printed foundry pattern or 3D printed metal part there is the  question of who is responsible for the shop drawings that detail machining process, finish and geometry? If its the designer than that moves his or her work into another dimension - understanding design intent, calculating fits and clearances and developing a complete set of shop documents. 

 

As I have pointed out before in other posts, the design and CAD component is probably 75% of the cost or greater. The actual printing is cheap. Here is an example:

 

This a magneto coupling. All I had to work with were dimensions from some badly corroded parts (and not all of them at that!) and a patent drawing. In this case I 3D printed a mockup assembly and also had to create the shop drawings. If I remember correctly I probably have 4 to 6 hours of billable time in this project which also includes developing models so patterns could be CNC milled or 3D printed. My time does not include the printing time. Depending on the hourly rate you can hit the $800.00 - $1,000.00 dollar mark for a project such as this fairly quickly.

 

The other question is the skills of the CAD designer. There are many people who can create 3D models but can they actually DESIGN the part? You pay for what you get and as I have said before people have a hard time forking over considerable cash for a few sheets of paper and a file on a USB drive. They have a hard time understanding that they are paying for 30+ years of professional experience, time, technical knowledge, expensive software and yes liability. In regards to mechanical parts make sure you are hiring a Mechanical Designer/Engineer. Not someone who designs jewelry or toys etc.  Its apples and oranges.

 

I like your concept so please don't take my words as discouragement. Its just things to consider: i.e. each client must be very, very clear in their expectations. Clients need to perform due diligence when selecting a designer and the designer needs to understand fully the scope of the work and expected outcome.

 

 

 

 

Edited July 22, 2020 by Terry Harper (see edit history)

[edinmass]

2 hours ago, carbking said:

While I have never used 3D printing, it seems to be a tool to maybe simplify production of a part.

 

BUT

 

The financial successful production of a part depends in a large part on demand.

 

As an example: I have a set of new old stock air valve springs for the Packard (Detroit Lubricator) carburetor used on a decade of Packards up to spring 1929. 40 years ago, I sent the samples to a "Mom n Pop" spring winding company and had 100 sets made to put in the rebuilding kits for those Packard carbs. It took 38 years to go through 100 sets. Now the "Mom and Pop" company has been inherited by the children who now want a 2500 piece minimum. Even if I could still get the 100 minimum, I would not redo these parts at my age.

 

To the OP - I wish you luck; however keep in mind the comments by others about quality. Somewhere the buck must stop. If one does not care about quality, "stuff" can easily be made in a country far away. And there are some who look only at the bottom line.

 

Jon.

 

Jon, I have an old employee who worked for me part time for twenty years. Full time he works at a spring manufacturing company. He will hand wind any quantity you like. A set up charge, material, and labor. He makes all our Stromberg springs.....if you want info, let me know. We ran springs for the 32 Detroit Super 8 carbs two years ago. I made twenty five springs.......and the price was workable. Ed.

[edinmass]

45 minutes ago, Terry Harper said:

This topic comes up often. As Gary stated its not simply modeling the part - there is a lot more to it depending upon the expected outcome which needs to be defined. For instance is the client satisfied with a rough casting versus a fully machined part? there is a huge difference between the two.

 

Same with using a 3D printed part as THE finished component or using it as a foundry pattern or a rough 3D printed part that requires machining. In all cases expectations need to be defined.

 

All of this greatly impacts the CAD designer and can impact greatly the cost. For instance if the expectation is a foundry pattern than as the designer I have to figure out the part lines, scale the component appropriately to account for shrinkage, add draft and machining allowance. Then whether its a 3D printed foundry pattern or 3D printed metal part there is the  question of who is responsible for the shop drawings that detail machining process, finish and geometry? If its the designer than that moves his or her work into another dimension - understanding design intent, calculating fits and clearances and developing a complete set of shop documents. 

 

As I have pointed out before in other posts, the design and CAD component is probably 75% of the cost or greater. The actual printing is cheap. Here is an example:

 

This a coupling for a magneto coupling. All I had to work with were dimensions from some badly corroded parts (and not all of them at that!) and a patent drawing. In this case I 3D printed a mockup assembly and also had to create the shop drawings.

If I remember correctly I probably have 4 to 6 hours of billable time in this project which also includes developing models so patterns that could be CNC milled or 3D printed. My time does not include the printing time. Depending upon the hourly rate

you can see that a part can get expensive fast.

 

The other question is the skills of the CAD designer. There are many people who can create 3D models but can they actually DESIGN the part? You pay for what you get and as I have said before people have a hard time forking over considerable cash for a few sheets of paper and a file on a USB drive. They have a hard time understanding that they are paying for 30+ years of professional experience, time, technical knowledge, expensive software and yes liability.

 

I like your concept so please don't take my words as discouragement. Its just things to consider: i.e. each client must be very, very clear in their expectations. Clients need to perform due diligence when selecting a designer and the designer needs to understand fully the scope of the work and expected outcome.

 

 

 

 

 

Fantastic response.........and 100 percent on target. 👍

 

[Gary_Ash]

There is high-end 3D printing available, including direct-to-metal, but the suppliers are aimed at industrial users, not us old-car guys (or is it old, car-guys?).  For a look at some of the materials, see this page:

https://www.materialise.com/en/manufacturing/materials

 

You had better want it bad because these are not cheap parts.  There are consumer-market materials that are made about the same way, but the suppliers warn that the parts are intended only for decorative applications, not critical function parts like pieces for auto engines.  That doesn't mean the parts are lower quality, they just don't come with a warranty - and still not cheap but possibly affordable for small parts.  Here's the consumer-oriented site of the same company:

  https://i.materialise.com/en

 

There are some parts that can be 3D printed that cannot be made by typical casting and machining, like blocks with thousands of tiny holes in inaccessible locations or a myriad of fine details.  Here's a sample printed titanium part by Materialise.  Don't try this at home, kids!