There are many ways to go about creating a physical object from an idea. Depending on the object’s purpose, the choices usually narrow down pretty easily. I will list some of the main options we have, and what they are good for.
If the object you have in mind won’t take too much stress, rapid prototyping with polymers is the way to go, and it’s usually the most common form of bringing an idea to life.
At work, we usually use an Objet 30 printer for most of our prototyping; this is a UV curable resin deposition printer. It basically has a head very similar to your everyday household inkjet, but deposits resin instead. The tray it deposits the resin on moves down as each layer (pass of the heads) gets piled on top of the last layer and a UV light attached to the heads cures the resin to a certain degree with every pass.
The results are pretty amazing as far as accuracy, and the material properties are good enough for general testing/use. We use them for general model representations, light/medium stress fixtures.
Stereolithography is like a "pool" of resin that gets cured at the very top. A plate moves each consecutive cured layer deeper in the pool, and the top layer gets cured as well. This process continues and is in essence a type of extrusion of cured resin.
The results are good, not as close as fused deposition, but acceptable. The advantage of this method is a wider variety of materials that approximate physical properties of real polymers. We use them for working model prototypes.
Selective laser sintering melts and bonds each powdered layer into shape. Much like the SLA principal, it extrudes the layers down.
The results are strong parts. The advantage of this method is that you may introduce a material fill/mix into your model, such as glass fibers, aluminum, carbon fibers, etc. We use these models for heavy fixtures.
You may choose this option if you’d like a larger quantity of objects. The initial cost for the mold is a bit more, but each consecutive part is far cheaper.
Depending on your physical object requirements, it may be necessary to have a part CNC milled, sintered and finished (via SLS), or formed with metal material.
The resulting parts are very accurate, very strong, but very expensive. We only use this for large fixtures.
Step 1: Conceptualize Idea
Step 2: Draw Parts
If the CAD software has finite element analysis tools, you may want to check the structural integrity of the object.
If this is an object which will interact with other parts, it may be wise to model the other items as well and see how everything fits together in an assembly.
I have the privilege of working with SolidWorks, and I’m happy to say it’s probably my favorite CAD software.
Step 3: Prepare for Prototyping
If you want to send it to a machine shop, you will have to make a detailed drawing, with all the necessary dimensions and tolerances (tolerances are very important and greatly contribute to the cost of machining your part).
Now, consider that I am at home and I don’t have too much money to spend on someone making a relatively simple part for me. What would I do? Well… enter wood! Wood is a great material for fabricating parts. It is readily available, easy to work with, fairly strong, and may be coated.
To begin making your part out of wood, let’s start with making a template to follow. This can be done by making a .pdf of the drawing (with the drawing views on a 1:1 scale, and make sure to at least center-mark any holes) and printing it out. I do this by making my drawing template an A4 and printing (with no special fit options) on a simple 8.5x11” paper.
Step 4: Trace Template
Step 5: Machine Features
Step 6: Finish Part
Good luck creating your ideas, and remember to always be safe while working with tools or chemicals!