How to avoid deformation of models with 3D printing

There is nothing “nicer” than moving away from the printer for a couple of hours and taking a nap, and when you come back, find this:

Plastic Spaghetti.

A familiar picture? Yes, these “spaghetti” obtained when the model is disrupted from the desktop. The cause of this disaster is often the deformation of the layers. Twisting the edges of the model upwards leads to the fact that the extruder catches the model and corny breaks or tears it from the platform. Next begins the artistic filling of the environment with a plastic thread in the artistic style of Jackson Pollock.

But the charms of deformation do not end there. What is the easiest way to embroil two makers? The correct answer is: ask them which is better – PLA (polylactide) or ABS (acrylonitrile butadiene styrene). ABS – a thing, of course, tempting. This plastic is durable, durable and inexpensive. Polylactide, in general, is also relatively inexpensive, but relatively mild and biodegradable – with all the ensuing consequences. So why such popular devices, like Makerbot Replicator, are created for printing by polylactide alone? Environmental sustainability PLA is a secondary reason, rather, even a bonus. And the main reason is a low glass transition temperature and minimal shrinkage. It does not require heating to ultra-high temperatures for melting, and when cooled, it shrinks, losing volume, but not much. In other words, it is easier to print polylactide. But ABS “settles down” quite noticeably, losing up to 8% of the volume. If you do not control the temperature regime, you can get bends and even cracks.

The list of rules to avoid problems during 3D printing:

Use a heated platform
Select the correct adhesion
Cleanliness is the guarantee of good printing
Height calibration
Better not to hurry
Do not chill out your model
Reduce the heat
Decrease the density of the model

Use a heated platform

This option is offered with many modern 3D printers, and in the case of RepRap the modification can be done by yourself. Let the heating and add to the cost of the printer, but it’s worth it. Heated model from below allows to slow down and equalize the cooling process.

Choose the right adhesion

If the plastic does not stick to the platform, wait for trouble. Which is the best, there is no consensus. The tables are made of aluminum, glass (even basalt), steel, titanium.

Cleanliness is the guarantee of good printing

If the working platform is covered with dust, then plastic will stick to the dust. How this will affect the grip of the model with the platform itself is hardly necessary to explain. If printing is done with ABS plastic, you can wipe the platform with acetone to dissolve the small pieces left over from previous models.

Height calibration

Correctly applied first layer – the cornerstone of successful printing. If the head is sitting too high above the platform when applying the first layer, the clutch may be too weak. This problem is solved experimentally: if your model is torn from the platform, try lowering the initial height of the head in small steps.

Better not to hurry

Yes, unfortunately, 3D printing of even small objects takes a lot of time. But in order to improve grip on the platform and give layers additional time for even cooling, you may need to slow down the printing process. This is especially important when working with PLA, because the polylactide cools long enough and the lower layers can undergo deformation under the pressure of the upper layers if they do not pass the glass transition point.

Do not chill out your model

Drafts make negative effect for your models. A draft can lead to an uneven cooling of the model – supercooling on the one hand, followed by one-sided shrinkage and crumbness. No wonder many manufacturers prefer to make enclosures for their printers. In addition, a tightly closed body helps maintain an elevated background temperature in the working chamber, which is good when working with ABS plastic. But when printing PLA, you may have to remove one of the panels or open the door (depending on how the housing is arranged) to facilitate faster cooling of the model.

Reduce the heat

The ideal option is to heat the extruder to a temperature just above the glass transition temperature of the plastic, so long as the extrusion passes normally and the layers “seize” with each other. After the more heated the plastic, the longer it will cool down, and the more tangible the shrinkage will be. But keep in mind that such experiments can introduce additional strain on the mechanism of the extruder, up to the damage of this one. Yes, and the nozzle can be hammered. Be careful.

Decrease the density of the model

The model can be homogeneous (a solid piece of plastic), hollow (walls outside, absolutely nothing inside), or lightened (in appearance, solid, and inside filled with plastic mesh or honeycombs). The latter option has a lot of advantages. Here, both material savings in comparison with whole models, good strength in comparison with brittle hollow models and, finally, reduced probability of deformation.