Month: January 2018

I’m Jason Firth.

Here’s an updated spool holder. I took some ideas from Geoff King who printed up a modified version that fit with more spools. It bolts directly onto the screw holes for the original holder.

I’m Jason Firth.

I printed off a set of braces for the towers of my Delta printer, and after installing them, found that the printer was all of a sudden failing prints. The kapton tape on my bed was utterly destroyed twice in a row, and the print I was trying to do just didn’t work.

My first instinct was to take a look at the home switches. They were wobbling around, so I figured part of the problem could be that my homes weren’t consistent.

I swapped the square bolts that come with the FLSun printer with actual T-Bolts. I immediately realized there was a problem: The bolts were not holding the part in!

I discovered that the back of the switch had these ridges meant to hold them into the 2020 strut.


I realized the easy way to fix it was to cut away part of the ridge. I used a simple razor blade from Home depot:


Afterwards, the t-bolts I purchased fit properly:


The switches locked in solid after this.

problem: My prints were still failing!

So I looked further. Next up I realized a basic maintenance problem: My belts were very loose. It worked much better after that, didn’t slam into the bed.

However, the print still failed, even though all these maintenance items were improved.

The final solution was to increase the layer height of my prints. I had it set to .06mm, but it appears that once I started tightening up everything, the printer simply isn’t capable of printing such thin layers. Perhaps in its sloppiness it was just barely slopping its way into each of the next layers.

I’m Jason Firth.

Yesterday, I had a revelation about my new printer. I was pretty happy with the prints I was getting (happy to be getting any prints at all, in fact) but the quality wasn’t quite where I wanted it.

I ran a check of the extruder calibration and found it substantially out. I asked for 100mm, but got 57mm instead.

I was already looking at calibrating the extruder, so I switched to the Marlin AC branch. That branch contains the latest developer patches.

Along the way, I had to move my config changes to the new firmware, so I had a deeper look. One change I made is to reduce the “slow” speed while calibrating. The stock settings shook the whole thing. I also increased the number of calibration points and changed the calibration routine to take each measurement 3 times.

One of the additions to the marlin-ac was automatic bed levelling. I assumed the auto calibration took care of levelling, but it seems that’s a different feature.

Someone in the flsun Facebook page suggested that my “delta kossel” and the “mini kossel” I keep reading about might be the same printer. It does seem plausible on second thought. However, it means that the example config is just completely wrong.

The other thing is that the flsun YouTube page appears to call the delta kossel and mini kossel different things. It’s difficult to figure out whether the two are the same or not.

This speaks to a fundamental of maintenance: defining your equipment. Giving it consistent naming, giving it a unique identifying number that functions within a system. For a company with perhaps 9 different products, this ought to be trivial. Perhaps a digit for product category (3d printers), one for product type (delta kossel), one for the subcategory (mini/standard/jumbo), a digit for model number, and a digit for revision number. “3ks1a” – easy. Then everyone can search for “3ks1a” and find Information directly relating to that printer.

In industrial automation, the ISA 5.1 standard defines similar naming. In industries around the world, this convention is used to name instruments in an immediately identifiable fashion.

Let’s look at a typical designation:

66-FIT-123

The 66 part of the above is area number. Very few plants are monolithic. Most consist of a certain number of defined areas with defined functions. These areas often have a single number associated with them. If 66 were for a certain power boiler, for example, anyone in that plant would immediately recognise that the instrument existed in that power boiler.

The second part, “FIT” above, is a standardized designation based on the ISA 5.1 standard. In this case, the first letter tells us the process variable. In this case, “Flow”. Other common process variables are Temperature, Pressure, Analytical, or Density. Each represented by the first letter of the word. The second letter above is “Indicating”. It is a modifier telling us that the instrument has a display. Finally, the last letter is “Transmitter”. This speaks to the function of the device. Often you’ll see Switches, Valves, or Elements. Sometimes you’ll see a Y, which indicates “special function relay”

Finally, the number “123” above represents the unique loop number. Every loop in the area will have a unique number, making it trivial to look for loop sheets, wires in a junction box, or PLC code.

In terms of the name you’d give it, I prefer following a few general rules.

1. Name for humans. This means naming things using natural language, and in a way that people can read. I’ve seen colons, dashes, And underscores in names. There’s no need for that. I’ve also seen things named something nobody calls something. Either correct your name, or change what people call the thing.

2. Name precisely. Calling stuff pump #1 is tempting, but makes things too difficult when trying to refer to something. “Boiler #10 feed water pump #2” tells someone everything they need to know about that device. Calling the printer the “Delta Kossel” is too broad. Every printer of this type is a “Delta Kossel”, and it appears the company has multiple kossel style printers.

3. Name consistently. Create a nomenclature or taxonomy and follow it. Don’t refer to the same device with six different names. In this case, the “Delta Kossel” and “Mini Kossel” might be different things. If they are, that’s fine. If they’re not, that’s a major failure of naming.

Anyway, I’m done playing with the printer until next weekend. Looking forward to the next steps. I’ll keep everyone updated.

Thanks for reading!

I’m Jason Firth.

I apologize in advance for the photos. No idea why they came out so bad.

Last time, I talked a bit about setting up my new 3d printer, an FLSUN Delta Kossel. The first day consisted of fighting with the firmware that was set up without any limits, and with some seriously wonky default settings.

I was able to complete my first 3d print, a ring from thingiverse, and then moved onto my second 3d print, a ball valve I designed:


Unfortunately, it didn’t print very well, and after printing successfully once, I wasn’t able to get it to print at all again.

I still had a few problems. The head wanted to dig into the bed. I tried to tape some magazine stock to the bed to protect the head and I tried to calibrate the bed that way, but that was a pretty poor solution. What I discovered is that there were a few problems with what I was trying.

The unit came with leveling springs, and the instructions on YouTube suggested I install them. This turned out to be a bad idea, because the nozzle contains a spring as well,and the two were fighting each other. I took out the spring, and because I’m concerned about the heated bed touching a bunch of plastic, I took one of the spare square bolts and used it as a spacer:


Next, I wasn’t happy with the auto calibration. The entire unit shook dramatically as it auto calibrated because of the huge amount of force needed to overcome the spring. I looked at the head and realized I didn’t have *one* adjustment, I had *two*. The silver set screw that set where the button releases, and the black set screw that set the spring tension:


I realized I’d have to calibrate the nozzle before I could run a printer calibration.

First, I loosened the silver screw until I heard the switch click, then I tightened it slowly until I heard it click again. I pressed the nozzle to prove the switch was actuating properly, because a couple times I just tightened it until I heard it click again but it didn’t reset with nozzle movement.

Second, I loosened the black set screw until the switch opened, then tightened it back up until I heard the switch close again.

After calibrating the print head, I was getting much better calibrations that didn’t shake the unit so badly.

Finally, to deal with the print head jamming itself into the print bed, I discovered a setting called Z-offset. I was able to change the z-offset from the unit faceplate.

First I went to the control menu:

 

Then the motion menu:

 

and Finally set the Z-offset:


I figured out the z-offset by setting my height (I used the faceplate in the prepare menu, but you could easily use Repetier to do it from your computer) lower and lower, until I couldn’t slide a piece of paper under the nozzle anymore. I set the Z-offset to the number of mm.

The final improvement I made was to place a fan near the bed. The unit has a fan built onto the nozzle, but this didn’t seem like a bad idea.

I was finally able to consistently make successful prints. Early on, I designed and built these clips so we can screw our undercabinet lighting to the cabinets:


And by the end of the day I had printed a spool holder I designed:


I was really happy how this one turned out. Not so happy about how the picture turned out, mind you. No promises how it will hold up once I place a 1kg spool on it instead of the smaller provided spool.

A few things I’ve discovered in a day of printing:

Don’t waste time trying to save material. A 1kg spool of filament has about 330m of filament. All the designs I’ve been printing use less than 10m of filament.

You see a lot of prints that look like they’re really substantial, but they might not be. The prints might be completely hollow inside. The above print has a 5% infill, so very little inside.

Shell thickness is your friend. I printed a tube with a 0.5mm shell thickness, and it was a great demo, but very quickly broke. I printed with 1mm shell thickness, and everything was much more substantial and is holding up much better. Given the choice between infill and shell thickness, I’ll choose shell thickness every time.

I didn’t need a raft or anything once I had the printer well calibrated. Suddenly the bottoms of my print were good by themselves.

Even though professional designers using molded plastic might use voids to conserve material, that seems to be a really bad idea here. I created an earlier spool holder that used a thick column with voids, and it was a really complicated print — it was constantly retracting and spooling out and ended up being really messy.

Today’s prints pushed the limits of a 40mm radius print bed, so I spent some time doing some tests. I figure I can safely print to 70mm without the print head or arms contacting anything, so I increased the print radius to 70mm in the marlin source code and re-uploaded.

I had a calibration error I couldn’t figure out — my Y axis was off, but only my Y axis. A post on the marlin forums suggested moving to the latest, so I moved to the nightly and re-uploaded. That worked perfectly. After upgrading, the printer calibrated happily and I’m ready for more printing tomorrow.

Because I don’t want someone like me to have to deal with the annoyance that was my first day, I took the configuration headers and submitted them to the marlin project for entry into the examples file.