Printer update

I’ve been busy blowing glass the past week or so, so haven’t spent much time with the 3d printers. I did print 8 more weight collars for the weight bench, installing 4 of them last week. They work really well and are easy to print. Printing 4 at a time is easy and takes about 2 hours. What  is even nicer is the new brand of filament is not jamming at all feeding the original cartesian printer, so I don’t have to monitor the print all the time.

The delta almost printed a nice cube. Only the base was off, and on reflection I think it’s because the setting for ‘probe offset’ is too large. The probe offset is basically the distance between the extruder tip touching the printer base and moving enough (into the base) to trigger the probe microswitch. There were two values in the Marlin firmware – 0.2 and 0.7. I’m using 0.7 right now and I think it’s too much, so when you calibrate the printer the final distances are out by a small amount. Not much, but just enough that the extruder is farther away from the bed on layer one than necessary for a proper first layer.

I need to spend some time with raw gcode to find the actual probe distance for my printer and then use that to recalibrate. Perhaps later this week or sometime next week.


FLSUN Delta not quite there yet…

I’ve been working with the FLSUN delta printer I built from a kit this week, and although it has printed a few of the test cubes, it’s still not quite fully functional yet.

It turns out delta printers are a lot faster than cartesian (x,y,z) printers, but with that speed comes some rather unique challenges. The first is that the printer, being tripod and pendulum based, really wants to print in an arc. To counter this, the software needs to know a lot of details about the printer, such as segment lengths and arcs in order to calculate various angles and offsets to use when printing.

Fortunately the delta code firmware I’m using (Marlin 1.1) now has an auto calibrate feature that works with the built-in z-probe on the FLSUN delta. Not all deltas have the z-probe, but it’s easy enough to add to any printer. Basically it’s a microswitch down near the extruder that detects when the extruder is near the print bed. On the FLSUN, the switch is triggered by a rather ingenious lever mechanism built into the extruder mount. When the tip touches the bed, it rocks slightly and trips the microswitch. You can fine tune the triggering pressure so that it’s very accurate. There is one compensating measurement you must take, and that’s how much deflection occurs when triggering. That is, the extruder doesn’t just touch the bed, it touches it a bit MORE than when printing to tip and trigger the switch. You need to know (in mm) how much this extra movement is so the software can compensate when calculating actual bed height.

The auto calibrate touches the bed in a set number of places that can be programmed (n*n, with n=4 as default). It can then calculate various angles and offsets that you then either save in the printer firmware eeprom or hand code into the software. I chose to hand code. The default calibration runs until a set standard deviation is achieved, so it’s quite accurate.

Once the auto calibrate is done and the information encoded in the firmware and uploaded to the printer, you can print.

My first prints were terrible. I quickly realized the extruder calibration was off. Extruder calibration is done with auto calibrate but must be done separately. Mine was barely moving, so after some experiments and adjustments, I got the correct parameter (stepper steps per mm of filament) and that was OK.

However, the next several prints were all still bad. I quickly found one of the three end stops that controls the position of the extruder was loose. After adjusting and tightening, things were much better, but there’s still a problem with the print.

The first few layers (about 1mm or so) are offset from the rest of the print in one direction. It’s consistent and repeatable at this time. The rest of the cube is perfectly straight, so it’s a “first layer” problem. So far I have not found any solution on the internet.

One hint that I’ll be pursuing is that the height measurement of the cube is only 19mm, while the sides are both 20mm perfectly. That implies again a “first layer” problem, possibly too hot. I am also considering the fact that this printer is incredibly fast. It’s almost twice the print speed of my first (cartesian) printer. It’s possible that it is simply printing the first few layers too fast, which may also affect the temperature of those first layers.

My next steps are to compare speed parameters between Marlin 1.1 (my current firmware version) and Marlin 1.0 (supplied with the printer) and my cartesian printer (also Marlin 1.1, but much slower settings). I will also try slowing the first layer in slic3r as a quick test. If slowing the initial print speed works, then that will be great. For now it’s a wonderful printer that has yet to realize all it’s benefits (and yet to make it’s first perfect print). 

“I guess I’m not their demographic”… Apple

I just had the most monstrous fight with apple software this week, and had to give up. All I wanted to do was prune my songs on my iphone and ipad. There were songs I wanted to remove that I had installed via itunes on my macbook some years ago.

Well, I couldn’t. Not easily. I finally used the general settings… remove all music feature to clean it up. The only other way was to delete each song individually by swiping left and then touching ‘delete’. Not whole albums, but song by song. How stupid and user-unfreindly!

The worst mistake I made was installing itunes on my Win7 pc. Dumb, dumb, dumb! It worked, but even after connecting the ipad and iphone, it would not let me actually TOUCH the songs. It was so brain-dead that after showing me “songs on the device” it would not delete – the only option was “copy to device”. BUT IT’S ON THE DEVICE AND YOU KNOW IT!!!

Today I blew away itunes. Of course apple left behind a puddle of other crap on the PC that I could not remove via programs. Fortunately I anticipate such nonsense, so before the install I had created a “before itunes” restore point. Using this I was able to recover my PC to where I wanted, not where apple wanted to leave it.

So now I have no songs on my i-devices, but I don’t care. The whole purpose was to use one as an alarm clock playing a random song each morning. Turns out it CANNOT be done via apple. The only way is to jailbreak the device.

As for apple, they don’t want me. They blew off objective-C for their own pathetic thingy called swift for i-device programming. That’s when I stopped app development. Then the recent crop of laptops (no desktops anymore) showed apple’s utter contempt for customers. “You can have light, or powerful, or good screen, but not all in one device. To get them all, buy more devices,” OK, I choose none.

Now the latest iphone is announced at a ludicrous price point. Honestly, the apple price and features list looks like it came from “SpaceBalls, the merchandising”.

Guess I’m not apples demographic anymore. Too bad. I really got the feeling that Steve Jobs understood me, what with us being the same age and loving tech and all. The new apple since Jobs just seems to be about “merchandising to the max”. Sad, really.

Letting the cat out of the bag (3d Printer)

OK, so I’m letting the cat out of the bag. Back in August I decided that I really wanted to try the new delta printers. They come primarily as kits, though you can buy one already  built if you are made of money. I’m not; besides I like building kits.

After much research including print and video reviews as well as many build videos, I chose the FLSUN Kossel Delta printer. There were several delta printers of almost identical value, but I chose this printer for the primary reason that it is “fulfilled by Amazon”, meaning that it comes from a N. American warehouse, not from China. That in turn means that it will arrive quickly. The price was also an incredible deal compared to many others.

It arrived in quick order, and everything was there. It was very well packed, and relatively easy to assemble. I did not make an “assembling of” video because those are pretty similar and all pretty boring, even at high speed. For the most part I followed the instructions to the letter, though I did deviate a few times when I could clearly see a better path. I only had to undo/redo one step, and that only because I wasn’t paying attention to the orientation of the extruder during assembly.

Some of the final steps were less than optimum, in my opinion. Mostly these involved routing and bundling of wires, and location of the main board and power supply. In the end I designed and printed some brackets to hold the power supply securely in a very nice location. I printed these on my other printer. I also designed and printed a spool holder to sit on top. There were available designs on Thingverse, but I really didn’t like them. I do like mine.

I will post photos of the spool holder and the power supply brackets later this week, as well as photos of the printer.

Once together, I did all the set-up, prep and calibration steps.

I still didn’t like the way I’d wired the power supply. I also didn’t like the fact that the power supply did not have an on/off switch, so I bought a switch/cord/fuse receptacle from Amazon (very inexpensive) and then printed a housing for it that sits off the end of t he power supply. It looks great and secures the cord (and all connections) inside the housing. Plus, now there’s an on/off switch for the printer.

I’ll post photos of the switch and housing later this week.

I have yet to make my first print with the printer, but it should happen quite soon.

3D Printing: more designs, fixes, prints and stuff

After printing the regulator flow knob, I was rather pleased with myself. Then the black filament ran out while printing a coaster, so I changed to the new AMZ3D filament I bought recently. I decided to try the white. The spools are smaller, both the hole and the width, so my current ABS pipe holder would not work.

I tried printing “from the box” as I’d done with the MG Chemicals filament, but it didn’t work with the smaller, side opening box. Instead it jerked the z axis at the start of a print and threw off the bed adjustment!

I managed to get that fixed, but took the opportunity to change the bed mount system to now use nylock nuts for greater vibration resistance. While I was at it, I again ran into the mess that is setting the z endstop.

So I decided to design a new adjustment system for the endstop. It uses the same new z endstop I printed a while ago and have been using with good results, but added a screw adjuster.

I designed the plastic to hold the screw using Tinkercad, then printed it. The first one wasn’t correct, but allowed me to see the problem and correct the design. The second was perfect. I mounted it on the non-motor x axis end that rides the vertical bar. One problem I discovered is the screw could not possibly touch the z endstop microswitch. I needed a lever, but turning the screw would spin the lever. I needed a round lever, a.k.a. a washer. Finding a suitable washer, I assembled the z endstop adjustment system and in the first test it worked perfectly. Better than that, it is now easy to make micro adjustments to the z endstop for quick adjustments of the extruder height. Photos attached.

Then I needed a new filament holder. During these test prints, I used a holder I made quickly from a bent metal coathanger (see photos) clamped to the table. It worked but looked like crap.

Today I designed a new spool holder, also out of a coathanger and a length of broomstick, but modified it based on what was wrong with the first one. It works great, and again photos attached.

All in all a great end of the week.

Awesome 3D Print

OK, I’m brilliant.

I have a SCUBA regulator that’s missing the flow adjustment knob. Years and years ago (2006?) I bought a primary second stage for my open circuit regulator set from a shop in Calgary. I got it for $100 even though it was brand new because someone unscrewed the flow adjustment knob and then lost it. I’ve been diving it that way ever since because you could not buy that knob for love nor money.

Last night before I went to sleep I thought… “why not 3d print a knob?”.

The knob fits a square shaft 7mm x 7mm x 2mm and is sized to match the regulator. It attaches with a 3mm  stainless hex bolt. Today I designed and printed the knob, and with a bit of drilling to open the bolt hole, it fits and  works perfectly.

3D Printing – it happened again

Yesterday I spent quite a while printing with great success, until the last print of the evening. By now the printer had been laying down filament for a few hours, and about 3/4 through printing a coaster, I heard the dreadful clicking sound that indicates a fouled nozzle. I immediately shut things down and called it a night.

Later on, while considering why the filament would jam after all the corrective actions I’d taken, it came to me.

My printer has one fan, which came as part of the extruder assembly I had purchased. Seeing there was a fan connector on the RAMPS board, I connected the fan there and found the slicer software would control that fan. The two settings were “always on” and “auto”. I had chosen auto.

Reading about auto mode indicated the fan speed was a function of print time per layer, determined during the encoding process. I thought this a bit odd, but figured it would be fine.

I asked my friend which setting he used, and indicated that his extruder fan was wired directly to 12v, and that the slicer setting was for a print cooling fan, not the extruder fan. Further reading of the RAMPS manual verified this. The parameters affecting the auto setting now made more sense to me, as you would want more cooling on a print where the layers are taking longer to print.

Further reflection also suggests why I was having problems. First, all my jams occurred after much printing, when things had been hot for some time. With the extruder fan not running all the time (auto setting), the heat from the extruder hot end would gradually travel up the metal feed tube. Eventually, the filament in the tube would become warm further from the nozzle. When this happened, it would be harder to feed the warm filament and it could resist and jam, much like trying to push a piece of hard spaghetti vs. cooked spaghetti. The purpose of the fan is thus to keep the feed tube cool so the filament remains cool and feeds properly.

Later today (after my dive) I will rewire the extruder fan to the 12V supply so that it’s running whenever the printer is on.

3D Printing – disaster and recovery

I have been experimenting with print settings for my 3D printer, to overall good success, until things failed.

The printer uses 1.75mm filament, which is heated and then extruded through a 0.4mm nozzle. However, it is possible to set the layer height to any value from 0.1mm to 0.4mm through the slicer software. The default was 0.3, but lower values are supposed to create smoother and more detailed prints.

Last week I stared printing with 0.2mm layer height, and things were going well. The prints did seem more detailed, but then disaster. During one print, I started to hear a clicking sound from the extruder. This is not good as it indicates the extruder is jamming somewhere and not feeding properly.

Checking the print I could clearly see that it had stopped printing. I killed the print and had a closer look. Filament was coming out the extruder gears where it should be feeding the heater & nozzle. In the end I had to completely disassemble the extruder so I could access the stepper motor, gear, pulley and filament jam. The extruder stepper was also very hot, which is not normal.

It took an hour, but I was able to disassemble, clear, and then reassemble the extruder. Unfortunately while reinstalling it I broke one of the printed PLA clips. I was able to glue it, but would need to print a replacement in the future.

With the extruder cleared, I printed the 20mm box without problems, so then started to print an octopus model. Midway through the print, the extruder started clicking again. This time I killed the print before the jam was bad and was able to remove the jammed filament without difficulty.


However, it left me with a problem: why was the extruder now jamming when it had been working fine for weeks?

I searched the internet for “filament jam” and found several common causes for jams, but only one really seemed to apply to my situation.

I had noticed the base layer was thin, and wondered if the nozzle height was too low. This is one common cause of jams, as the low height prevents smooth flow of filament in the first layer. After testing I realized the nozzle needed to be raised by 0.1mm or more. This is not easy with my current z endstop, but there’s a parameter in the slicer software to include a “z offset”. I did this and the base layer was much better on some test prints.

However, this was not the case before the first jam. I had checked, and removing and reinstalling the extruder had changed the nozzle height just enough to cause the problem. But that did not explain the first jam.

I therefore reflected on the classic problem solving approach, “what changed?”. The one thing I had changed was lowering the layer height from 0.3mm to 0.2mm. As I considered this, it seemed to me a puzzle – why would you think you could get 0.2mm from a 0.4mm nozzle? Should not the nozzle diameter dictate the layer height, not the other way around? You do want adhesion between layers, so it seems logical to use a number like 0.3mm for a 0.4mm nozzle, just to squeeze the layers together a bit. I had been using 0.3mm for weeks without problems, so the logical next step was to return to 0.3mm and see if filament jams ended.

I did that a few days ago, and since then have printed more objects than I have in the weeks before. Every object has printed very well, with good quality, and NO JAMS. So 0.3mm it shall stay. I even printed the new extruder clips and have installed them.

I’ve even stared playing with “vase mode”, where prints are a single layer thick and a continuous spiral of filament. The vases are paper thin, but really fun to make.

So it would seem that I’ve solved my filament jam problem.