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After a while, everything wears out, 3d printer components included. I noticed, not too long ago, that my bowden tube kept slipping out of the pneumatic fitting attached to the extruder. Whenever the extruder would feed filament it would push the tube out too.

Upon investigation, I found that there are little “teeth” inside of the pneumatic fitting the keep the tube in place. Pushing down the little plastic ring disengages the teeth and allows the tube to slip out. Over time, the teeth had worn out and needed to be replaced. On most extruders, this is a simple fix. Just find the right size pneumatic fitting and replace it.

I see a lot of people wondering why their 3d prints have little zits and voids in them. One of the potential reasons is because their filament has collected moisture. Filament is porous and collects moisture over time. Most filament manufacturers do a pretty good job of ensuring that filament is dry when it gets to you, but not always. Usually, moisture is absorbed when filament sits around in the house for a while.

When water is heated to 200 °C, like when you are printing with PLA, it turns to steam and then escapes, leaving little pockets on the surface of the project.

To ensure that you don’t have to worry about this, make sure that your filament is dry. You can do this by vacuum packing your filament if you aren’t going to use it for a while, using a filament dryer or food dehydrator to dry out filament before use, and keeping desiccant near the filament to absorb the moisture from your filament.  

Sometimes you just have to lay down a lot of filament. I make large structures for my boys, where details aren’t really that important and it’s ok if you can see layer lines in the print. When I print these, I like to switch from the 0.4mm nozzle to a 0.6mm nozzle to accommodate more filament being put down. However, there are a couple of adjustments that need to be made.

  • Slow down the speed a little bit. The bigger cross-section of the extruded filament takes a little longer to heat up. Slow down to give it time to heat. Even with a slightly slower move speed, you are still putting down 1.5 times as much filament so your net speed is still much higher.
  • Increase the temperature at the nozzle. You have increased the nozzle diameter by 1.5x. The center is going to cool down a little bit faster than with a 0.4mm nozzle.

When designing parts for 3d printing, make sure they will fit together. Sounds like common sense, but I hear of a lot of people trying to fit a 1/2″ pin inside a 1/2″ hole. Unless your intent is to get an interference fit, it won’t work.

From a design perspective, you need a small clearance fit for components to fit together. You can either make the hole larger or the pin smaller.

From a manufacturing perspective, your perfectly round pin that is exactly 1/2″ on your computer isn’t exactly round or exactly 1/2″. Depending on a lot of variables, it’s going to be slightly oversize or slightly undersize. How much will really depend on the process that you choose, the materials that you use, the environment that it’s in, the condition of the machine, etc. In addition to extra functionality like extra print heads, closer tolerance control is probably the biggest reason why a $10,000 3d printer costs so much compared to the little hobby printer that I have at home.

There are a couple of things that you can do to improve your tolerance. Maintain your equipment, get better equipment, level your bed, maintain your environment, buy good quality filament, etc. You should also run a tolerance test. You print a couple of parts that have gaps in the cad of varying sizes. If your 0.020″ gap is fused together, then that is your limit. It’s good to know your limit.

Symptoms of a poor bed level include:

  • print not sticking to the bed
  • nozzle scraping bed
  • thin or see-through first layer

When I get this, there are a couple of things that I check. First I check the printer mechanically:

  • Disable any BLTouch probing
  • Level the bed using a paper or feeler gage
  • Create mesh bed level manually
  • If troubleshooting, run a test print.
  • Enable BLTouch probing
  • Create automatic bed level
  • Run test print

From following these steps, you should be able to accurately diagnose where the problem with your bed level lies. Address accordingly.

This tip is so specific that I’m surprised that it has come up as frequently as it has. For context, many people use Klipper on a Raspberry Pi to manage their 3d printer. There are two main interfaces for Klipper, Mainsail and Fluidd. This tip is for those who are set up with Mainsail.

When moving your 3d printer to a new wifi network, there are two things that I do. With the Raspberry Pi powered off, remove the SD card and put it into your laptop or desktop computer. Ensure that you don’t use Notepad or Wordpad to edit the file, as they tend to bring in characters that mess up files. Use something like Notepad++ instead. In the root directory of the SD card you will find a file called mainsailos-wpa-supplicant.txt. Open that file in your text editor and change your network information. Most common nowadays is WPA/WPA2.

The other optional step that I do is to log into the router and set up my Raspberry Pi as a static ip address instead of letting DNS manage it. Each router is different, so I won’t go into detail on how to do that here. Most routers have something like “Advanced networking.”

I’ve seen a number of help requests lately that have to do with clogged nozzles. I’ll share how I go about unclogging nozzles, but I will also share how I deal with clogged nozzles afterwards.

To unclog a nozzle, the first thing I do is heat up the hotend as high as the software will allow. This can help break down any clogs that may be in the nozzle into smaller pieces and allow them to pass through. Next, I’ll take a small pin or needle and carefully push it into the nozzle and try to remove any material that I find there.

If that is not successful, the next thing I will try is a cold pull. Heat the nozzle up and then let it cool down completely. The idea is that (hopefully) any impurities will be absorbed into the filament so that we can pull it out when it solidifies. Next, I typically remove the bowden tube connection so that I can pull on the filament directly. Heat up the hot end and start pulling gently, but firmly on the filament. You will feel it start to give at a certain temperature. Pull it all the way out and cut the tip off. This should remove some of the impurities that were previously stuck in the nozzle. Do this 2-3 more times.

If you are not successful with either of these methods, I just replace the entire hot end. For most hobby printers, hot ends cost $10 – $20. I usually keep a spare on hand and just swap it out.

When working with a bed level, sometimes you find that your bed is level but it is not flat. Mine, for example, is raised in the center. Because of this, it is impossible to use a standard bed level procedure. You need to use a mesh bed level. This feature doesn’t come enabled on all printers, I had to update my firmware to be able to do a mesh bed level. How a mesh bed level works is it breaks the bed down into smaller “tiles.” On mine, the tiles are approximately 60mm x 60mm. This allows the compensation to follow the contour of the bed instead of assuming that the bed is perfectly flat. As I always say, don’t try to solve a mechanical problem with software. Level your bed first, as best as you can. Then incorporate the mesh bed level. Make sure that you heat up your bed for 15-30 minutes before you do the mesh bed level so that your bed will take the shape it will be in while printing. Store your bed level profile and make sure that you activate it before you start printing. I typically do a new mesh bed level in the summer, in the winter, and anytime that something significant changes on my printer.

So, what’s a good amount of deviation for a mesh bed level? A good general rule of thumb is 0.1mm. If you can get your deviation at 0.1mm or better, then (for hobby purposes) you are doing pretty good.

Someone recently showed a picture of their 3d printed 25mm calibration cube. Unfortunately for them, however, it was not a cube at all. It was a 25mm x 12.5mm x 20mm shape. 

When digging into the problem a little bit, it turns out that they had changed some stepper motors and firmware and accepted all of the default values. If the firmware has not been specifically written for your printer, the default values are most likely wrong. Same thing for the stepper motors. If you replace stepper motors, make sure that your X, Y, and Z steps are correct. Using Marlin based firmware, you can set your X, Y, Z and E steps in the firmware before flashing or you can use the M92 command to update. Using Klipper firmware, you must set your rotation distance.