Have you ever needed a part that just doesn’t exist? Did the ‘carpet monster’ eat a critical part? Is the AM kit just not available to you? Here is a way to get around all of these problems. Most reviews cover a kit, a part, or a product; this one covers a process. The company www.printapart.com offers a service that creates a part that you design. You can see their vendor profile here.
I tried the process on a recent project and will give you my feedback on the entire experience.

Overview

You design a part in a 3D modeling software. You submit your data file to www.printapart.com through a web interface. They print your part on a 3-dimentional ink-jet printer – the Invision HR 3-D Printer. You wait for the mail man to deliver your part to your door.

3D Software

The one big test in this whole thing is the software. Availability and education are two high hurdles in this race. If you’re reading this review online the first hurdle (availability) is a low one. There is a free version of a 3D modeling software available for download called Alibre Xpress. You can download it here https://www.alibre.com/products/ - make sure you download the Xpress version.

There are other pieces of software that you can download and use; I found this one to be the easiest and most straight forward. In your quest for a piece of software make sure it can create a Stereolithography files (*.STL). This is the only file type that will work.

Design

Here is the fun part of this adventure - education. Getting the software is easy; using the software is a higher hurdle. This is not a cut&paste, drag&drop proposition. You have to commit to this. It is not unlike pouring your first resin part or sculpting your first figure. It is a learning process and if you think of it as an investment in your ‘bag of tool tricks’ it will pay off in the long run.

Will your first part turn out perfectly, well, it will turn out better than your first scratch resin pour. The beauty of the 3D software is that you can ‘see’ the part before you buy it. You can make different versions easily and quickly and compare the two side by side.

To help you design your first part Alibre Xpress has some very nice tutorials. Along with the tutorials is a user group forum much like ModelGeek’s forums. In here you can search for answers as a lurker or join and get interactive help. You can check it out here.

Designing your first 3D part is a lesson in patience and a trip back to 10th grade geometry. You have to think about things in a totally different way. You have to think about things like the radius of an angle or curve, how a solid shape will interect with another. It’s a bit like a model. There are sub-assemblies and details that all combine to make one final ‘thing’. With a car model, it’s a body, a frame, an engine; with a 3D part it’s; planes, lines, features, sketches, shapes.

I choose to ‘build’ a cannon barrel for my project. While I was designing it I had to think about the profile as one component, the axles as another, the ball at the end as yet another. All in all there are nine components that make up the barrel within Alibre.

Design Summary

Designing a 3D part could be a series of features all to itself. Just know that with a bit of patience and some friendly internet help you can run this race and learn this process. You just have to commit to it. For my barrel I have about ten to fifteen hours of time in just designing the part. On top of that I have a few hours in learning the software itself.

Your focus will change when you use this technology. When you have a scratch built piece you tend to put a lot of effort on the back end of the process. You add details and textures and refinements to an almost done part. With this process you put your efforts in the front end of the part. You design it and refine it and add details before you have something that you can pick up and hold.

Web interface

Once you have created a part and exported or saved the data into a .STL file you will work with www.printapart.com ‘s web interface. I give these guys a ton of credit here. The web interface for managing print jobs is great.

This is a straight forward site; you set up and account, and manage your data. If you’re reading this, you’ve come very close to doing everything Printapart will require.

The user account setup is easy; you enter all your personal information to set up your account. Don’t worry – you are on a secure site when you do this and when you manage your projects and request a print job. After you login, with your email address, note that your connection becomes a secure one. You can see this by the change of the address in the URL from a standard “HTTP” to a secure “HTTPS” and from the lock icon in the bottom right status bar of the Internet Explorer program.

Once you are logged in there is a full suite of tools to upload your projects and manage what you will buy. The best feature is a price quote before you commit to purchasing a part. Another nice feature of the site is the longevity of your projects. Project data that you upload stays active and available for up to a month (if I remember correctly), print job quotes last a week. This gives you a chance to rework your part if it’s too expensive or too big for the printer. You can also upload multiple versions of your part so you can cost compare adding detail or changing the resolution (size).

One thing I need to bring to your attention is the Print Priority field. This is how quickly www.printapart.com schedules your job in the production printing schedule. It reflects how fast the ‘print’ button is pushed. Don’t confuse this with a shipping priority. In the process you set the Print Priority first, then the shipping methods.

The last part is arranging the financial options and committing. Then wait for the mail man to come.

What you Get

You will get an amazing product. First of all – you get what you designed. Whatever you have in the .STL file comes out. It’s really pretty amazing the first time you do it.

The part comes well packaged and you shouldn’t worry about it breaking in transit.

Inside the box you’ll find a light blue part(s). It is lightweight and very similar in texture and consistency to a resin part. The material has a firm soft feel to it. It’s quite comfortable.
The material is totally ‘workable’ using standard modeling techniques, sanding, cutting, gluing, and painting. You will need to use CA for gluing purposes. Prior to painting you should wash the piece one final time.

This material is easier to add to your arsenal than PE or Plaster. The tools you have will work with it, the CA you have will work with it, the paint you have will be fine.

I found that there is a ‘grain’ to this material. If you ‘slice’ thinly and with the grain it is very much like wax. It ‘peals’ or slices very easily. If you work against the grain the material is very firm. This has to do with the ‘layers’ of ‘ink’ that are printed. Each layer creates a ‘grain’ that can be pealed back. I have tested the durability of these pieces by leaving one in a hot garage for a long period of time. There was no ill affect of this. The product will degrade if too hot. I was trying to mimic a ‘realistic’ environment that would occur for a number of members.

my barrel

My recent Sparrow project included scratch making a canon barrel. I thought that would be a great comparison with this process.

As mentioned, your focus is shifted to the front end of the process. Scratch building my barrel using conventional means was very back end heavy. What I mean by this is that I spent more time worrying about details and ‘finish’ at the end vs. the beginning. Pouring resin will result in over pour, seams, excess flash: all of which can be removed later.
With printapart you have to consider size, shape, detail and fit up front. If you want detail you have to design it in up front in the software.

From what I can recall I didn’t spend any more time on either process. They were about equal. They were equal enough so that I didn’t feel I was spending more time on one vs. the other. The first time I made an RTV mold was a circus, and was time consuming. The first time I tried to design a cylinder in Alibre was worth the prices of a ticket to a show. Once I went through the tutorials and practiced, things got much easier. I have to say that mistakes are easier to fix on the computer version. No remolding, no re-turning or wasting raw material. Just delete and reenter. It’s a wonderful feature to be able to view two different version based on the same part. On the computer it is very easy to save one image, adjust it then bring them both up.

The big difference was that I couldn’t physically touch the computer version. That was strange to me at first.

The cost aspect of this process is reasonable. You won’t go out and replace all your scratch building techniques, however, this will definitely find a spot on your workbench. There are ways you can reduce the cost or keep it to a minimum. To minimize cost you can use a lower resolution reducing the file size and thus the amount of material. You can have a very thin wall to reduce material. There are FAQ’s and tip on their website to help you with these ideas.

wrap up

This whole process is another tool that everyone should keep in mind when looking for a specific part. It is like pouring resin, or scratch building from stock styrene; you won’t use it for everything. If you have a part that just isn’t commercially available, or one you lost, or one you just can’t create: this process can.