3D printing is a fine art in a world full of beginners. Fortunately the internet is full of support and sympathetic ears from other printers.
There are many ways a print can go from a Pinterest – perfect picture to a plastic spaghetti pile. Recently Simplify 3D released a printing guide that covers the full range of issues that you can face. Different brands of 3D printers are known for their quirks that cause their own problems. Kit built printers are notorious for having all of these problems. Among these problems I’ll cover the ones I ran into on my Makerbot 5th gen and Lulzbot Taz 5 printers.
1. Problem: Not Extruding at Start of Print.
When you start printing, the filament has to be hot enough to flow into the nozzle of the print head. If your temperature settings are off for your material, it may not melt enough to flow into the head. Check the info from the filament manufacturer for the recommended settings for each filament material. When in doubt, I found it better to run your filament on the higher end of the temperature range. For example, if I’m printing PLA/PHA, the recommended range is 190 – 210 C and I run it at 200 to start.
Fix 1: Check you temperature settings, especially when you change filaments from PLA to anything else.
Fix 2: Check that your build plate is level and offset correctly. If the head is too close to the build plate, you’ll see track marks in the blue tape. In Makerbot Desktop it can adjust the offset under the device settings. For Lulzbots, you have to adjust the offset manually.
2. Problem: 1st layer is not sticking to the bed.
The first layer is the important foundation to your print. Always monitor your print to make sure this layer goes down flat and smooth. If your print has complex curves, circles or tight angles on the base, you will really need to monitor your 1st layer.
Fix 1: Slow down your print speed. I know when you have a long print it is tempting to throttle up your printer. But if it goes faster than the plastic can bond, you end up with a stringy glob around the print head.
Fix 2: Clean the build plate. I use blue painters tape on my build plate, and sometime the tape loses the ability to grip the material. Other printers use glue stick, hairspray, acetone, or kalpton tape to hold the print to the bed. You have to experiment with what works with your printer to get something that works consistently.
Fix 3: Heating and cooling. My first printer, a Makerbot 5th gen, had a unheated glass build plate. Without that slow plate heating, the PLA shrunk like mad, especially on the first print of the day. Other materials like ABS you have to keep warm while printing or they will warp. Lulzbots thankfully can heat up, which will give the plastic time to bond to the build plate. For cooling, check the fan settings. If the fan is full on at the start, that may be cooling the plastic too quickly. You can change the settings in the Gcode.
Fix 4: Brim and rafts. Small prints, or prints with holes and complex shapes will need a brim or raft to hold them in place. With all the complex curves, the shrinkage will pull holes out of alignment and keep the shell from sticking to the plate. Explore using brims and rafts on different prints to decide what works best. Use brims if you have to use supported prints. Use a raft if you have a large or odd shaped flat print.
3. Problem: Over / under extrusion.
This is a problem when going between different materials and diameter of filament. While Makerbots are set at 1.75 mm filament, Lulzbots can run 1.75 and 3 mm filaments.
Fix 1: Check the settings on your slicer. I occasionally forget to do that on the Lulzbot when I go from 3 mm to 1.75 mm filament. The difference causes a thin string (under extrusion) or thick wavy blob (over extrusion) in the layers. You have to cancel the print and restart if this happens.
Fix 2: Check the flow rate. If it is over or under constantly, the print head motor may be running like it’s supposed to (Makerbot “Smart” heads are notorious for this). You can play with the flow rate to see if this helps.
4. Problem: Gaps in top / bottom layers
Gaps in the layers make your print look like a sieve, and makes the print brittle. I’ve done this when I try to rush prints by making every shell and layer as thin as possible.
Fix 1: Thicken the top and bottom layers in your slicer.
Fix 2: Use more infill to support the top layers. Large gaps between infill supports are hard to bridge and can droop, leaving you with bulges or lumpy quilting textures on the top of your print.
5. Problem: Grinding filaments.
You are printing when you hear a steady “click, click” sound from the print head. If you have a Makerbot, that sound is the famous click of death from the “Smart” head. That click sound is the filament catching and grinding against the hobble bolt.
Fix 1: Check the temperature and make sure you’re printing hot enough for that material. All printers will try to force filament into the hot end, but if it does not melt you will get a jam and grind the filament. This is what kills the “Smart” heads on Makerbots.
Fix 2: Use a pick or toothbrush to clean out the teeth of the hobble gear.
Fix 3: Check the filament to see how brittle it is. Bad filament will chip and break instead of bending with the hobble gear. I’ll write more about bad filament in a future blog.
6. Problem: Clog / jam.
This is the hardest thing to fix, because the jam tends to happen deep inside the hot end of the print head. If you hear a clicking sound and don’t see any material coming out, you have a jam. Makerbots are infamous for jamming inside their “smart” extrudes due to electronic and quality issues.
Fix 1: While the head is still hot, unscrew the nozzle. This will open it up to hopefully clear the jam on its own.
Lulzbot Fix: On Lulzbots you can open the idler arm and pull the filament out while its hot. If you have a problem you will see it on the end of the filament. Hopefully you can remove any kinked or bad filament from the head without having to clean out the whole head.
If that does not work, the jam is caught at the start of the hot end. You’ll have to break out the Allen wrenches and dismantle the printer head. Carefully use a drill or punch to get the jam out of the body.
Makerbot Fix: On Makerbots you can try to reverse the filament jam through the printer controls. When that fails, your “Smart” head may be jammed to death. You can try drilling it out after you remove the nozzle (which will void the factory warranty). After this, take a shot of hard liquor and call Makerbot customer support. You can also try a guitar E string to try to floss the jam out, but that will also void the warranty.
This is the short list of problems I have encountered while 3D printing with Makerbot 5th Gen and Lulzbot Taz 5 printers. Check the support for your particular brand for printer specific issues.