Design Tips

3D models present some significant design challenges. We would love to help you by providing some basic tips for you to keep in mind. Of course, it is always a good idea to know the specific properties and quirks of the material you are working with. In our case, we working primarily with ABS. Many people also like to work with PLA.

There are also many different programs that you can use to 3D model. Check out different modeling software to see which works best for you!

Overhangs

Overhangs are one of the biggest issues that people face with designing 3D models. If there is not enough material below a layer of filament, the filament will droop and create a distinctive pattern found with overhangs. There are many different ways to deal with it, many of which are documented on our page for Dealing with Overhangs.

Chopstick effect

Tall, skinny objects can have a lot of trouble printing. These objects are not always very stable and may start to wobble the higher they get. The extruder may knock the model around, especially if it catches a stray piece of filament, and a layer may be printed messily. Because each layer is so small, a messy layer means the next layer has no good base on which to print. This effect cascades up through your print, resulting in messed up prints.

Even if your object is mostly stable, your layers may not be large enough to allow time for each layer to cool. If you print on top of a layer that is too hot, the layers tends to sag into each other. This is especially important if you are trying to make interlocking pieces because the dimensions will be somewhat distorted.

The easiest way to resolve these problems would be to print your model on its side, if that is possible. You may choose not to do that for aesthetic reasons, but never fear! You may still be able to print your model.

Taking your time with tall, skinny objects allows each layer to cool properly and form a sturdier model. You can set a minimum layer time in your slicer settings, found under the filament settings: slow down if layer print time is below. By default we use 30 seconds as a minimum layer time. If this is still not good enough, you can try printing a second model at the same time. The time the printer spends printing the other model allows your first model to cool properly. This gives you a better chance of a successful print.

Assemblies

It can be tricky making multiple parts that fit together. Most materials tend to expand when heated and shrink when cooled. Filament is no different. This shrinkage is especially prevalent in ABS, which means parts often come out a different size than was modeled. It can take some experimentation to find what allowances work best for your setup.

Printing assemblies is not impossible. With some practice, you can design things like the Solidoodle belt, which can print several links at the same time, preassembled!

Strength

Having trouble making ABS parts strong enough? Remember that when parts break, they will most often break with the layers of plastic. Design your layers perpendicular to the stresses on the parts and they will be far more strong.

Another great way to reduce stress on corners is to incorporate fillets and chamfers into your object.

Of course, even a well designed piece can break if you don't also use the proper infill.

Speed

In general, tall and skinny objects take longer to print if they are printed standing upright than if they were laid on their side.

Try to hollow out any extra material. Even if you reduce your infill to a very low percentage, it will still take significantly longer than a hollow model. Consider whether or not the infill is necessary- can you design your own [[[designing support structures | support structures

Warping

Warping is an issue that most people have to deal with. There are many ways to avoid warping, but one of them includes editting your model.

If you suspect that your print will warp in a certain place (like at the corners), you can add small, one-layer-thick circles around corners. This increases the surface area of the corners, allowing them to adhere to the bed better and resist lifting.

Warping can also occur in very solid, dense regions as different sections cool at different rates. Removing excess material within your model by adding holes will reduce the amount of pull on the outer surface, reducing deformities.

Sticking to the Bed

Make sure your model has a nice wide base to help the first couple of layers stick properly. You can try adding a brim to your model when you slice it, but you can optimize your

Layers

If you have aesthetics in mind, imagine designs that will work with the "layered" look of the ABS. A great example of this is the printed spool holder mount on the Solidoodle 2. While this spool holder mount isn't threaded it looks like it should be. Layers become less noticable with smaller layer heights. The trade off is a significantly longer print time.

You can still remove the layer look by applying different finishing techniques.

Simplicity

It can be tempting to increase the resolution of your print by increasing the polygon count of your 3D models. We've used models with up to a million polygons, but this will depends on your computer. At some point, refining your model won't make a difference to the actual printed model. Consider decimating some of the polygons in your model so that the software is not overwhelmed.

Simplier models will both slice faster and print faster. It is easier for the printer to print long straight lines than a wavy line of the same length.

Details

We use a 0.4 mm diameter nozzle.

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