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I switched filaments. I’ve been meaning to change my nozzle, so while I was in there I did that too. When I printed a test print to make sure everything was good my first layer had holes in it.

Here is what I had to do to fix it.

  • my new nozzle doesn’t necessarily have the same height as my old one, so I releveled the bed and reestablished my mesh bed leveling.
  • my new nozzle probably doesn’t have the same heating characteristics as the one that I replaced, so I tuned PID.
  • my new filament may not feed in quite the same way as the old one, so I updated my e-steps.

Sometimes, you just can’t get the part quality that you want. For whatever reason, your machine just is not capable. Whether it is because your overhangs cause you to have to use a lot of supports which leave ugly marks on the surface, or your machine just doesn’t have the resolution to leave a good finish. There are a few things you can do.

  • Tune your machine. Make sure that 25mm commanded in the gcode results in 25mm of material printed.
  • Split your model into pieces. I print a lot of figurines for my kids. The hands and arms prove to be particularly difficult, as they need to be supported and they are small. When I cut the arms off and print them separately, I have much better results, then I just glue the arms onto the model.
  • Primer/paint. A little paint covers a multitude of imperfections. 

The final intent of the part is going to drive a lot of decisions in the 3d printing process. 3d printed parts have become very useful in improving prototyping and developing new products. However, as the cost of 3d printers has come down significantly over the past decade, or so, many hobbyists (like me) have also started buying 3d printers. I’m sure I’m not alone in this, but I use my 3d printer for all kinds of stuff. I make figurines for my kids’ games. My wife wants a new decoration for her curtains and can’t find any that she likes in the store, 3d printer to the rescue. I also use if for functional parts.

End use drives many decisions, such as:

  • material selection: for functional parts, I tend to use ABS. For the figurines that I create for my kids or decorative items that I make for my wife, I tend to use PLA
  • layer height: for decorative parts especially, I like to use a very small layer height to allow my components to be as smooth as possible in the Z direction. If I’m just creating a quick prototype and don’t care if there are obvious stair steps on the model, I might increase the layer height
  • speed: in my experience, higher speed = more vibrations, and more vibrations = lower part quality. There are a few things that you can do to dampen vibrations in your printer, but you will need to adjust your speed based on the final use of the part

 

 

I’ve run across a couple of posts where people are having trouble with different things. Upon digging into it a little bit, I have found that they are using the wrong temperatures for the materials that they are trying to print with.

My post today is pretty simple, use the temperatures for the filament that you are using. If you are using PLA, use temperatures in the PLA temperature range. If you are using ABS, use temperatures in the ABS temperature range. Most manufacturers provide their recommended temperatures on the side of each roll of filament.

The optimal temperature will vary some and will depend upon your setup and your ambient environment, but you can’t run PLA at 260 degrees and expect a successful print.

It’s not secret that 3d printers rely on heat, and that they need to have a constant source of heat. So, what happens when the temperature outside gets colder?

If you live in a temperate climate where the winter temperatures aren’t that different than summer temperatures, lucky you. You probably don’t need to do much, if anything. For the rest of us, we’ll probably need to make some adjustments.

I live in Texas, you will need to experiment for yourself to see what works best for your own situation, but this is what I do in the winter.

Set up my enclosure. Summers here are hot and the enclosure holds in too much heat. In the winter, though, I need to keep all the heat in so I put my enclosure back on. Turn up my bed temperature by 5ish degrees to help adhesion. I also include a G4 (dwell) command in my Cura start script to give my bed a little more time to heat up. Usually, 5 minutes dwell time is sufficient to get the whole bed at a stable temperature.

When 3d printing, the filament actually is extruded when laying down a surface (obviously). But when the printer needs to skip across a hole or change layers, it actually retracts the filament into the nozzle for a short period of time. This is a good thing. If these settings are off or if the printer were to stop retracting, you would find a stringy mess of filament across every hole or void in your print.

There are two settings that I want to describe:

  • Retraction distance: this is the amount of filament that the printer pulls up into the nozzle. As you can imagine, timing, speed, and retraction distance are all related. If your retraction is set at 6mm, but your acceleration and speed are set so high that the printer only has enough time to extrude 3mm you are going to see some issues on your print, which brings us to the second point.
  • Retraction speed: this is the speed at which the printer retracts the filament. Set it too high and your extruder might strip your filament. Set it too low and you will have stringing.

One of the best ways to optimize your retraction is to print a retraction tower. However, printing a retraction tower requires you to update your retraction settings at certain intervals in Z. If you don’t have the ability to do this, trial and error is another alternative that gets you pretty close. Just update your retraction settings by a small interval and see if there is an improvement.

 

“Dad, the fence is down again!”

We live in a rural area and have animals. As anyone with animals can tell you, there is always something breaking, always something to do. Whenever possible, I like to have my boys (ages 10 and 13) fix it. I think it teaches them responsibility and gives them problem-solving skills. 

In this particular case, a fence bracket had broken. I could easily have gone to the store to pick one up for a few dollars. But miss out on this great opportunity to teach my boys something? Nah, not me. I had been looking for an opportunity like this. Something that needed to be custom made. A part that was pretty straightforward, but did need to be a certain size for it to function properly. This bracket needs to fit right, but it would also be forgiving. After all, it’s just a fence.

My boys had tinkered in Fusion 360 before, but it had always been just to create random toys and things that didn’t have a specific function.

“Go get my calipers from my toolbox and meet me outside.” We talked about how to measure parts to make sure they fit together and how to make sure that you have gathered enough dimensions. Then I turned it over to them to design. After many trips outside to confirm measurements, we had a design. Then we 3d printed one. It worked, the very first part off of the printer worked.

Whether they end up as engineers or not, these boys will have some valuable skills.

For Christmas, I’m making the famous leg lamp from “A Christmas Story” for one of my family members. He’s always been a big fan of the movie and the leg lamp has become a running gag between us. 

However, making the lamp does pose a few unique problems. One issue is that I will need to run an electrical wire through the leg itself to provide power to the led light that I will put in it. I figure I have two options, I can either put a hole through the leg in the cad and then print it that way, or I can change the print settings. What I’m trying first is to create the leg with 0% infill, but I’m increasing the number of exterior walls to compensate. Hopefully this provides a leg that is still structurally sound, but allows me to put the wire through the inside of the leg.

I had a mishap recently which required me to remove my bowden tube from my printer in order to clear out a clog. Upon reassembly, the tube kept popping out of the connector whenever I would try to print something.

As it turns out, there are tiny little “teeth” inside of the pneumatic connector that keep the bowden tube in place. When I removed it the first time, I smashed some of the teeth and prevented it from grabbing the tube properly.

In order to fix the situation, I replaced the tube itself (been meaning to do that for quite a while) and the pneumatic coupling.

There are a lot of ways to find interesting things to print using a 3d printer. Thingiverse, or other stl repositories are abundant with files to download and print on the printer. You can commission an artist to create something for you. Join a Patreon group that creates figurines for your tabletop game. But, sometimes you can’t find what you are looking for online or just want to create your own.

There are many available tools, with more being created all the time. But, there are two that I use consistently.

For functional parts, such as when I create 3d printed widgets to replace broken things around the home or when I create photo stands for my family, I use Fusion 360. It’s subscription based, but it still seems to provide the most tools and provide the ease of use that I’m looking for. In fact, it’s so easy to use that I often have my 10 and 12 year old boys make stuff instead of doing it myself. I look at this as a valuable learning experience for them, especially if they ever end up in some type of engineering role for their careers.

For more artistic parts, I use Blender. Blender has a pretty steep learning curve, but there are tons of online resources available to help with that, including many video tutorials.