If you’re new to 3D printing, the choice of printer is just the beginning! These are some tricks of the trade that I’ve learned along the way.
- I’ll be referring to temperatures in Celsius because some printers and many filaments reference Celsius only.
- This guide focuses on filament printing.
Filament vs Resin
A filament printer uses the long strands of plastic, typically on a spool. A resin printer uses a liquid resin plastic that you pour into the bottom of the machine. The primary advantage of resin printers is print fidelity. Resin printed objects will be smoother.
The 2 primary filament types that every printer will accept are PLA and ABS. PLA is a plant based filament that melts at a relatively low temperature (190-200C). It is very easy to print with and relatively inexpensive. ABS is a harder plastic and requires higher temperatures (220C+). The resulting prints can be stronger structurally because ABS is stiffer than PLA.
Another common type is PETG, which will be considered if you want to print transparent objects in particular, but a wide variety of colors are available. PETG requires even higher temperatures (260C) to print well.
If you plan on painting your prints, filament color doesn’t really matter because you’ll have to apply primer paint before painting. If you want some interesting looking unpainted objects, consider a rainbow or “shiny silk” silver or gold filament.
Also pay attention to the filament thickness when buying. Check your machine, but the most common and widely used thickness is 1.75mm.
Inserting the filament for the first time is a straightforward affair. While waiting for the nozzle to come up to temp, snip the tip of your filament at a 45-degree or steeper angle. Once the nozzle is hot, slide the filament in until you see some spewing from the tip.
Changing the filament became my first disaster on my MP Mini Delta. I pulled the filament back when attempting a filament change. This resulted in a clog.
The correct technique:
1. Heat the tip. Go hot – to the max filament temperature listed on the current filament.
2. Release the spring/gear pressure on the filament.
3. Grasp the filament near the entrance. For about a half second, PUSH IN. You should see some filament spew from the hot nozzle.
4. PULL BACK IMMEDIATELY. As soon as you see the nozzle spewing, pull back at least a couple of inches.
If you don’t do the push, the pull will leave the nozzle clogged. Simple once you know… Painful to find out the hard way.
Following is a list of recommended tools and their purpose:
- Elmer’s glue – This is used to stick the object to the platform.
- Painters tape – Stick this on your build plate before applying the Elmer’s. Keeps the original surface clean and smooth.
- Pliers – handy for snipping filament and when you have to do some disassembly.
- Tweezers – Detailing printed objects
- Old cloth or t-shirt – cut into small squares to apply the glue to the painters tape.
- Guitar string – to clear a filament clog. My Creality printer came with a tool that substitutes, but I like to have extra if and when that one gets bent.
- Spray paint – If you plan on painting the objects, you’ll have to prime them first. I use a Rustoleum that is designed for plastic.
- Acrylic paints – Acrylic will stick well and is easy to paint with once the primer is on.
Sticking the Print
I began using the Elmer’s glue method shortly after I began printing. What tends to happen is that the higher the print goes away from the bed, the cooler it becomes. This causes the plastic to warp. There can be some forgiveness for this, by letting the build plate give slightly and the excess filament flowing into the internal matrix of the print, but eventually the print can break loose from the bed before printing is complete and is ruined.
My first couple of short prints went well. This really came into play when trying to do taller prints of more than an inch or two. They fell over continuously until I applied the tape and glue method. Now I almost always glue, with at least a thin layer, even when doing short prints.
So here’s the method:
- Apply the painters tape – you don’t have to cover the entire build area. Cover enough so that the area for your print and a little extra area is around so that the glue stays on the tape. Apply the tape in strips, butting them up next to each other. You can recheck your leveling at this time. However, I have found that applying the tape flatly does not result in any tangible change to the print.
- Preheat the bed – The hotter the better. My MP could only achieve ~52C although it promised 60C. The Creality can achieve 60C so do it.
- Prepare the cloth – cut a piece of cloth from a t-shirt or similar. Use a cloth that does not have lint or strings that come loose in the glue.
- Wet the cloth with hot water – Get the piece of cloth in hot tap water and ring it out. It doesn’t have to be too thoroughly rung out, but give it a good squeeze in your fingers. I usually keep the cloth balled up after squeezing to retain the heat.
- Apply the glue – unfold the cloth, take the top off of the Elmer’s, and dump it on to the cloth. Don’t be afraid of too much.
- Smear it all over the print area. Again, don’t be afraid to use too much. There should be a visible layer on the tape.
- Begin printing immediately.
Finishing the Print
When your beautiful print is finally finished, you may notice that it is not so beautiful. Complex prints that require a lot of print head movement, will result in “strings” of excess fillament hanging everywhere. Sometimes just trying to grab a handfull of these and pull can break a print. You can use tweezers and files to work the rough edges down. I use a set of clay sculpting tools to smooth out the edges. If you try to use a Dremel or similar, the plastic will simply melt and appear beside the area you were just grinding.
Applying a detailed paint job to your object brings it to life. But don’t just try slapping the paint on. Acrylic paint doesn’t really want to stick to bare plastic. Use a primer first. Several layers may be necessary.
After the primer, acrylic paints will stick nicely. However, be aware that watery paints can exhibit a capillary effect of sorts, and may “flow” into the layered grooves of the print.