Tag: 3dprinter

I’ve seen too many printers pulling up pieces of their bed along with their print when they go to remove it. There isn’t much you can do about the damaged bed, but you can prevent it from happening again in the future. I have found that such aggressive bed adhesion often is the result of too much “squish” in the first layer, temperatures being too high, or a scored bed surface.

  • Wait until the part and bed are completely cool before attempting to remove. Don’t do what I did when I first got my printer and take a spatula and try to force it under the print to remove it as soon as it says “printing 100% complete.” After the part and bed are cool, if it still doesn’t come off easily, I use compressed air sprayed at the base of the part. It is cold enough coming out of the can that it causes the part to shrink away from the bed and separate.
  • Adjust your temperatures. 
  • Take good care of your bed surface. Use isopropyl alcohol to clean it with lint free cloth.

I talk a lot about getting the most out of your 3d printer. But, how do you know if your 3d printer is capable of doing the job? Sure, if you are making a Christmas tree ornament, who cares if it’s an extra 0.5mm too thick? What if you are making a functional assembly? Or, what if you are building a prototype for a component that needs to fit inside of a housing? Is your machine capable?

One way to know for sure is to do a quick tolerance analysis. Rather than looking at the machine capabilities only, you can now design with certain tolerances in mind. Based on what you know about your machine variability, you can design components so that, even with the variability from your process, you can still make parts that will fit. Or, you can know if your machine is incapable of making the parts you need, in which case you need to come up with an alternative manufacturing process.

Have you ever looked at your 3d print and wondered what those little patterns are in the sides of your print? It’s possible that they are artifacts from resonance in your X and Y axes. Resonance, meaning that your axis is vibrating, which means that your nozzle, which rides on the axis, is also vibrating, which means that you are transferring those vibrations to your print.

There are a few things you can adjust.

Most printers have off center holes in the bearings that the axes ride. This is done intentionally, so that you can adjust the tension. Make sure that your bearings are tight. Make sure that your belts are tight too. Try wiggling the motors, the print head, the bed, and the vertical supports. 

What does this have to do with resonance compensation? I’m a believer that you can’t solve a mechanical problem with software. If something is loose, don’t try to apply compensation, fix the problem.

Even after you have a mechanically solid machine, however, you will still have some resonance remaining in the system. I believe that this is what resonance compensation is for, not to mask underlying mechanical problems.

A lot of people are wondering why their prints are not sticking to the bed when they haven’t changed anything on their printer. I’ve mentioned bed leveling many times, but that’s usually the first thing I look at. The other things I look at are extrusion temperature, bed temperature, and bed cleanliness. Many people put their printers in a basement or in a garage. If there are no temperature controls on the environment, it could become a significant problem. A couple of things to look at as the weather starts continues to get cooler:

  • ensure that your bed is very clean. I use Isopropyl alcohol with a lint free cloth for PLA
  • make sure that your bed is level to the frame
  • in the wintertime, I usually increase my extrusion temperature by about 5 degrees. Your results may vary, so experiment with this on your own machine
  • enclosure, if you feel like you need a jacket, chances are that your 3d printer needs to be warmer too

A couple of days ago, I wrote about calibrating your extruder with Klipper. Today, I would like to talk about how to calibrate your extruder e-steps with Marlin firmware. Here is how I do it:

  • Move printhead to center of bed and about 150mm off the bed
  • Mark a spot (I use tape) on the filament about 125mm down from the bottom of the extruder
  • Use calipers to measure actual value of tape from extruder. We’ll call this “A” and say we have 126mm for this example
  • M503 – read current values and make a note of the current E value. We’ll call this value “B” and say we have a current E value of 400 for this example
  • M83 – enable relative mode on extruder
  • G1 E100 F100 – feed 100mm of filament at 100mm per minute
  • Let it finish the extrusion and measure the distance between the bottom of the extruder and the tape that we marked. We’ll call this value “C” and say that we have a current value of 24 for this example. If everything were already calibrated correctly it would be 126 – 100, or 26mm.
  • Calculate our new E-Steps value. 100 * B(A-C) is the formula. Substituting our values from this example we get 100 * 400/(126-24) = 392.16.
  • Update our esteps on our machine with M92 E392.16
  • Save our new value with M500

A lot of people push for Capricorn Tubing on their Bowden system. In fact, I have it myself. I recently found out about an issue that surprised me, but it makes sense when I think about it a little bit more. Capricorn is known for having high precision, tight fitting tubing to connect the extruder to the hotend. Using Capricorn tubing solves a lot of feed issues and ensures consistent prints, or does it?

What happens when you have a high precision tube that fits around filament with significant width variation? That’s what some printers are experiencing. The solution? Printers are finding that they either need to switch to more precise filament, or that they need to switch to a larger diameter Bowden tube.

After I rebuild my hotend, I always calibrate my extruder esteps. Every extruder, nozzle, Bowden tube, heatbreak, and filament has a slightly different flow rate, so this is something that I do pretty frequently. The process is pretty simple and straightforward.

  • Move the print head at least 100mm above the bed
  • Using calipers, mark off (I use tape) a spot around 125mm on the filament
  • Measure the exact length of the filament
  • Command the extruder to extrude 100mm
  • Measure the amount that is left
  • Calculate the actual that was actually extruded
  • Update rotation_distance for the extruder

Ideally, you would have a drive system for your filament that is:

  • lightweight
  • responsive
  • durable
  • does not obstruct or adversely affect movement of the printhead

Unfortunately, you have to choose. You can’t have all of these qualities. Each setup has pros and cons and every 3d printer needs to decide what is best for them or accept what their printer comes with.

A Bowden system mounts the extruder off to the side of the printer frame, allowing the printhead to be more lightweight, which allows higher speeds and acceleration. The tradeoff is that you have a tube that connects the extruder to the printhead, which makes accurately controlling the amount of extruded material more difficult (think trying to turn off a lightswitch with the end of a broom handle).

A direct drive system is just the opposite. You get more responsiveness with your extruded filament, but you are adding weight to your printhead.

If frequency were the only indicator, you would guess that printing different versions of the Venom Symbiote was my favorite thing to print. I’ve printed green ones, black ones, and in this case, I printed a transparent one.

I had to completely rebuild my hotend after this one, over a very simple mistake.

I had purchased a new hotend (complete) to replace one that I was having problems with. I put it on my printer and started printing and you can see the results for yourself.

What I forgot to do is “hot tightening.” When assembling the hotend together (at room temperature) you screw in the nozzle and the heat break until they touch. My heat sink also has some setscrews that need to be tightened. At room temperature, everything is tight. However, when things heat up and expand, little gaps in between each of the components will occur. The solution to this is to heat up your hotend to around 20 degrees beyond what you intend to print at, and then finish tightening the components.

After trying to print a QR code over the weekend, I decided to tune in my retraction settings. Step 1, I printed a retraction tower. I printed a tower with different levels, with retraction distance set at 0mm, 2mm, 4mm, 6mm, 8mm, and 10mm.

2mm of retraction was a clear winner for my machine, so I decided to dial it in more. I printed another tower at 1mm, 1.5mm, 2mm, 2.5mm, 3mm, and 3.5mm. 2mm was again the clear winner for my machine, so next I decided to play with the retraction speed settings. Most source recommend a retraction speed of 35-40mm/s. I printed a retraction tower with speeds of 30mm/s, 35mm/s, 40mm/s, 45mm/s, 50mm/s, 55mm/s. 40 and 45 both looked pretty good so I printed another one that ranged from 39mm/s – 44mm/s.

Judging from the towers that I printed, my optimal settings are 2mm at 42mm/s.