For a while now, I have been thinking about designing things such as small bedside tables, game/dvd/bluray racks for 3d printing. I've always thought that making them modular would be a good way to go about doing this as well.

Modular design would help to create an end result that is vastly larger than the print volume of my 3d printer. I might even be able to recycle models for use in other projects. However, I'm not sure of what I need to think about if I decide to go ahead with these ideas I have floating around in my head.

I'm assuming that certain joints (dovetail, etc), tolerances for different types of plastic due to shrinkage, and print settings (% infill, in particular) would be important to have thought about and evaluated to some extent, but I'm not sure about what else I might be missing.

So my question is to anyone who has designed anything to be modularly printed. Have you really had to think carefully about the engineering side of the print? Or am I simply overthinking this? Should I just design what I want and give it reasonable infill, walls and whatnot, and just go for a trial and error approach? I'm sure there is a method to this madness, but is a concrete understanding of this type of engineering absolutely paramount when it comes to this sort of stuff?

EDIT: Although I've marked darth pixel's answer as accepted, I'm still going to follow JKEngineer's advise and check out that book as well since I feel as though proper engineering techniques alongside a good mentality towards how I would tackle the problem (as outlined in darth pixel's answer) would prove to yield better results in the long run.

  • $\begingroup$ I am not sure what you are asking? Are you asking about design of a 3d printed object? If so this is probably not the best area, and a mech engineering forum might be better. $\endgroup$
    – StarWind0
    Aug 23, 2016 at 16:21
  • $\begingroup$ There seem to be two questions going on here. One is "How to make a modular design?" and the other is "How do I make sure stuff fits together"? Your response to @darth_pixel's answer seems to suggest the second one was actually your question. Perhaps you can edit your question to make it a bit clearer what your question actually is. $\endgroup$ Aug 23, 2016 at 21:40
  • $\begingroup$ I don't see how that is 2 separate questions, since if I'm designing something to be modular then I want the pieces to fit together. $\endgroup$ Aug 23, 2016 at 21:41
  • $\begingroup$ I've edited the question. I'm not sure how I can make it more clear $\endgroup$ Aug 23, 2016 at 21:46

2 Answers 2


All printers are designed with an idea of WYSIWYG for sure. Depending on:

  • printer - type/quality/settings/configuration/assembly precission
  • filament - type/quality/shrinkage
  • user skills - manual/using app proficiency
  • model complexity
  • environment conditions and so on

you can get different results.

I venture to say users know their printers (after some time and by trials and errors) so they know how to manage dimensions to compensate all above so you will get this knowledge too.

Mathematical formula can describe shrinkage of the material, all other elements are very hard to describe (mathematically) in a general way.

Of course someone can simplify it and say: more money you spend better effects you'll get. It's sometimes true ;)

So all your modular things will be better and better if you will increase (what is to be increased) in above points especially "user skills".

Is engineering paramount? It depends of whay you gonna create. If your modular things have to lock itself, have to have threads, screws and such stuff then this is engineering. Is it the most important part of the design? Not necessarily.

I would say 3D printing moved engineering to next level. I'm talking about this or this. Is it still art or engineering? :)

This is my receipt:

think > imagine > design > rethink > redesign > give it a try > get back to thinking

good luck

  • $\begingroup$ Great answer! Really reminded me of why I got into this in the first place. So, in essence, collectively, practice makes perfect and I should have a "measure twice, cut once" mentality? $\endgroup$ Aug 23, 2016 at 15:31
  • $\begingroup$ Also, just curious, what about my question were you not sure about? I'd like to know so I can improve my future questions. Thanks :) $\endgroup$ Aug 23, 2016 at 15:32
  • $\begingroup$ @JakeMillington if you think my answer is good then it means I did understand you correctly. And yes - practice makes masters. $\endgroup$ Aug 23, 2016 at 15:35

A book you would benefit from reading is "Functional Design for 3D Printing...Designing 3D Printed things for everyday use - 2nd Edition" by Clifford Smyth.

It deals with FDM printing only. It deals with considerations of orientation of the parts being printed to address required strength in the 3 directions (x, y, z), tolerances, and designing parts in such a way that they can be assembled, have the strength needed, have flexibility, etc. In some instances he shows how to split a single functional part into multiple parts so that, when assembled, it actually performs as required.

It's available from Amazon at Book on Amazon. I received it as a present and have no commercial interest in it.

Here's a review: Book Review on 3D Printing for Beginners


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