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). 

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.

Photos of recent 3D prints

As promised in my last post, here are some photos of the weight plate collar and the new regulator flow knob. Also a photo of the old knob for comparison.

Dacor Fury small knob

Dacor Fury new larger knob

Weight plate collar (the yellow spot marks an original collar)

This is a set of base brackets I printed to hold my PiDP8 kit at a better viewing angle (design from Thingverse)

Still designing and printing

I made a few things this past week, and designed (and made) a few others.

First, I didn’t like the stark white of the new Dacor Fury flow adjustment knob, so reprinted it in black. I also flipped it so the square hole was on top for a better print of that side. When done it fitted perfectly and has already been tested in the water. It works perfectly.

I loaded cave line onto the dive spool and also took it in the water. It held up perfectly but time will tell how it holds up.

I also designed and printed a replica of the weight plate ring for my weight bench. The ring is a complex plastic part that sits in a hole in the weight plates and keeps things from banging loudly when in use. Each plate requires three (on for the center bar and two for the side slide bars) and many were missing or broken when I bought the (used) weight bench. I tried contacting the manufacturer in eastern Canada, but the bench was made in 1995 and they had no records for it at all! I designed one in Tinkercad and it printed perfectly. It’s now on the 50lb plate so that it can get some everyday use to see how it holds up before I print more.

I also designed and printed some clips for the cats’ litterbox. It’s 10 years old and the originals broke. The printed ones fit perfectly and so far are holding up very well.

Finally over a week ago now I designed some small plastic ‘buttons’ to cover assembly holes in a set of drawers Linda bought for her sewing room. You know the ones – the small white plastic 1/2in buttons that go in the screw assembly holes in pre-pack particle board furniture. This one was missing all but one (of 8) so I used it as a template to make 9 new ones. Some had to be white glued in place as the holes had enlarged, but all are on now and look great.

I notice that my photos weren’t ready for uploading, so I’ll add them soon. (New reg knob, loaded dive spool, weight ring and litterbox clips).

 

Lastly, some news on filament. The white AMZ3D filament was working very well, with only occasional snags. Thinking about it, I realized the spool did get loose during the coathanger holder creation. I decided to open the AMZ3D black filament and be very careful loading it. As a result, I’ve been able to print many things, some with over an hour print time, without any snagging at all. It would seem that a) this AMZ3D filament is awesome stuff, and b) loading procedure is critical – you cannot get any loosening of the filament when loading or you will get snags. I really like the AMZ3D white, but I absolutely love the AMZ3D black. I even ordered another roll.

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.

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.

3d Printing – chicken and egg

Last week I designed another gear item for my camera and underwater housing. The 60mm focus gear works perfectly, but I was curious if my 17-85mm zoom lens would work in the housing with the current port.

The problem with ‘just trying it out’ is that while I can put the lens on the camera and fit it in the housing & port, I know that at 17mm there will be vignetting as it’s not a dome port. What I really wanted to test was whether or not it could zoom enough to be useful. However, just trying to install the lens zoomed might not fit. What I needed was to be able to actuate the zoom with a proper zoom gear.

Which meant designing and printing a proper zoom gear. Based on my focus gear design, I created a new model based on the focus gear cylinders, but sized for the zoom lens which had quite a bit larger diameter. The zoom lens also has a noticeable bump where the autofocus switch is located. After a few test prints, I completed the final design and printed it. The first print was very good, and fit perfectly.

With the zoom gear complete, I was able to install the lens on the camera (with zoom gear) and then into the housing on wide angle. Once in, I could clearly see the vignetting, and then tested the zoom gear. Again, it worked perfectly, but the lens quickly bumped the end of the port. Sadly, it was nowhere near close-up, and still showed vignetting. In the end I will not be able to use the zoom lens in the underwater housing with the current macro port, but if I ever win a lottery and buy a dome port, it will work perfectly.

 

In other news, I’ve been watching a lot of youtube videos on “delta printers”. These are 3d printers that employ a triangle pillar system to control three stepper motors, which in turn move a trapeze supported on the three pillars. It’s a very fluid moving system, and most fun to watch. There is one new version that has one extruder but three filaments, and can mix colors on the fly!

Watching build videos it’s clear that some of these printers are extremely well designed for kit building. The only downside at the moment is there are very few inexpensive kits that offers both heated bed AND multiple extruders. The best kit I’ve found so far (for build quality) comes with only one extruder and no heated bed. While the heated bed is pretty easy to add, conversion to multiple extruders is a very advanced topic. The other downside is many come direct from China, and that’s always a bit of a crapshoot when it comes to the thing actually arriving at my door. So far I’m around 90% but still… to lose a $300-$400 kit would not be good.