Artsy thingy: check!

I guess it had to be done at some point. Artsy print, accomplished. Twisted flower vase by Yellasing.

Came out pretty good considering I had to scale it down to around 30% of the original size.

PRINTinZ printer plate

On another note; I'm extremely pleased with the printer plate from PRINTinZ. I'm using the 140x140 mm printer plate which fits my printable area quite nicely.

The prints stick extremely well to the surface even when printing cold (PLA). Although too little clearance between the hotend and the surface might have it stick too well on thinner prints so be careful.

Failed print, not because of the printer plate though.

It is great to be able to lift out the whole printer plate instead of having to fiddle inside the printer when removing the print. Detaching the print from the plate is surprisingly easy. Instead of having to use a sharp knife you just twist and bend the plate and the print pops right off - as long as it's not too flexible.

The above part is 120mm in diameter and that's the biggest footprint I've managed to print to date. Previously the parts would always pop off before the print was done - even with a heated print-bed and using kapton or blue tape.

A funny thing is that when I removed the plate and placed it on the table, before removing the part, it was quite warped by the print. The finished part is a bit warped, but in this case it won't matter, but it's something I'll have to look into in the future.

Having dialed in the new E3D v6 hotend the new setup is starting to look quite nice - best quality prints so far :)

Another Rebuild

It seems most of the posts on this blog has been about me rebuilding my 3D printer. Well, hopefully this will be the last one in a while as I have several other projects that are in need of parts and I'd rather spend time on them than on another teardown/rebuild.

I were quite happy with the performance on my previous extruder mechanism, although it was supposed to be temporary. Combined with the J-Head I got very nice prints for a while.

When the extruder broke down I tried a couple of e-bay replacements but did not quite get the performance (or fit with my printer) I was looking for. At the same time the J-Head started acting up (leakage and stuff) so I needed to find a replacement for that as well.

After a bit of research I ended up buying a Bulldog Lite Extruder from their Indiegogo campaign and was pleasantly surprised that they shipped them right away with no waiting at all. Although a bit heavy it's beautifully machined and well put together. The "Lite" comes without the gearbox which makes it a bit lighter, but is only suitable for 1.75mm filament. Secondly I ordered the E3D v5 hotend which has gotten great reviews. Going with an all-metal-hotend made sense this time around since there's no peek or PTFE that can melt/be deformed.

One thing about about the Bulldog / E3D combo that isn't perfect is the mating between the two. They are both fabricated to follow the J-Head "standard" so you can just slide the stem into the extruder, but there's quite a bit of slack along the z-axis so I made some shims out of regular plastic. 4 of these did the trick.

It took me a while to get everything put together, as I also switched the printer firmware from my stock Sprinter firmware, delivered with the SUMPOD, over to the latest Marlin.

Now I finally have a working printer again. And I must say, I'm very pleased with the quality of the prints as well as the new functionality in Marlin. The printer even sounds better!

My first print were a camera stand for one of my Raspberry Pi's. This print was sliced with .3 mm layer height so it's a bit rough, but I opted for speed before beauty this time. I've made the design available on Thingiverse as well.

Until next time!

New Spool Holder

I had some 8 mm carbon rods laying around and figured my 3D printer needed an upgrade for the spool holder. The rods are nice and long (50 cm each) and I originally intended them for a quad copter build, but I found rc-helicopter tail-rotors made of aluminum to be a better fit for that project.

Finished contraption.

The whole printer/spool holder assembly is quite high, but it saves space on the table at least. It's this high by design since the y-axis moves back and forth and having a bit of distance between the print head and the spool is good in that case.

Closeup of the spool holder.

For the center rod I used a threaded rod. This makes the centering of the bearings easier and also adds to the stability by allowing us to tighten the hold around the bracket from the vertical rod a bit.

Oh, and it rolls so much better than my last try. The design can be downloaded from Thingiverse.

Largest print yet

I finished a 15-hour print yesterday. As it didn't finish Sunday, we had cinema tickets and I really don't want the printer to be running when I'm not in the room, I had to pause it and continue yesterday.

Designed in Autodesk Inventor

Pausing the print didn't pose a problem, except for the operator error. I wanted to increase the distance between the print head and the part, while the head cooled down, and indadvertedly pressed move z 10 mm in the wrong direction... The print head buried itself well and good into the model, but when I reversed the direction the damage wasn't too bad. After a bit of cleanup the next day I could continue the print. Kinda lucky there.

The print came out pretty good, except for two layers around the point where I paused and that's totally my fault. By being more careful I'm sure pausing a print will cause no artifacts in the future.

This print took quite a while and I'm pretty sure I can increase the print speed since it clocks in at about 14 mm/sec at the moment. If only there was an option in Slic3r where it would speed up on longer stretches and then slow down around bends or where it goes back and forth rapidly. One for the wish list.

Oh, and what is it you might ask? Its a new stepper motor holder for the y-axis on my Sumpod.

Finally printing again

After several months of not printing I finally have a working 3D printer again - Yay! I can only blame myself for this; since I in my eagerness to improve the printer tore it apart before printing the new parts I needed. Even though my J-Head arrived swiftly I had nothing to mount it on...

J-Head Mk V-BV. Excellent build quality!

The aluminum plate mounted on top of the slide-bearings did not have enough stability using zip ties alone. I tried replacing the zip ties with brass wire (the sort used to hang paintings with), but that turned out even worse since you can't get the wire tight enough.

My best friend Sugru at work again.

Enter Sugru. I had a batch in the fridge that was nearing it's use-by date so why not try that. I made sure to protect the bearings with scotch tape so the sugru wouldn't stick - only support. Apply healthy amount of sugru and wait 24 hours. Worked like a charm!

Next I needed a new mechanism to feed the plastic. The easiest would have been to print something, but without a working printer that proved ... difficult.

Initial setup with the spring mechanism.

After a lot of thought and a fair number of iterations I came up with a design that let me have a spring as tension mechanism on the filament feeder.

Need more springs Scotty!

When calibrating the feed rate I quickly discovered that the original spring didn't have nearly enough force to keep the flow of plastic consistent - especially when the filament spool needed to be unreeled by the printer as well. Adding three more springs fixed that issue neatly - although it doesn't look as pretty any more.

First print: new tension lever.

First thing I printed was the Minimalistic Mk7 replacement by +Whosa whatsis. This is so I have a replacement part ready for if when my cobbled together setup fails.

As for now the feeder seems to hold up pretty good as well as consistent results. I think I'll keep it for a while. The J-Head I'm really impressed with; great build quality and excellent print result!

Print head progress report

Just a quick update regarding the print head from QU-BD. First impression was really good: the assembled hot- and cold end looked professional with a thought through design. I was very eager to try it out, but started off simple, just hand-feeding the filament without engaging the motor.

At 180C the plastic flowed perfectly for about 10 cm (raw filament) - then abruptly stopped! Even using pliers I could not force any more filament through the nozzle. Pulling out the filament I noticed a small plug at the end. Cutting this off and re-threading the filament let me extrude again, but as soon as I made a stop, or after about 10 cm, it would stop again. Feeding and then retracting before feeding again helped some of the time, but no matter of increasing/decreasing the temperature made any difference.

After a lot of fiddling and reading the various threads at Fabric8r I concluded that there was no use even trying the motor before I disassembled the print head. Which was easier said than done considering the plastic had leaked and clogged up the inside of the heater block. Instead of warming it up I soaked it in isopropanol over night - which kind of worked.

Leaked plastic.

More plastic at the bottom and inside.

It's hard to see in the pictures, but you can see the plastic around the brass nozzle and at the top of the heating block. This being caused by the brass nozzle and steel rod not being pressed together tight enough. The leakage apparently causes drag inside the nozzle and makes the plastic hard to press out through the nozzle. When stopping the PLA will expand in the heat and cause total blockage.

Fixing this should be easy enough, cleaning the parts, re-tighten and reassemble the whole thing. Although I'm not going to do that. I'm sure one can get nice prints with this head, but after reading about all the other issues people on the Fabric8r forum are having with not just the hot-head, but the feeder as well I can't be bothered. All very fixable I'm sure, but requiring a lot of fiddling and even then the prints tend to not be that stable between sessions.

So being kind of fed up not being able to print I decided to order a new print head. This time a more proven design: the J-Head Mk V-BV recommended on the RepRap wiki. The one I ordered has a .4mm nozzle and is made for 1.75mm filament. A .4 mm nozzle (the same as I've been using from the beginning) should be easier on the motor as well although I won't be getting as fine details as with a .35mm nozzle (like in the QU-BD head). The bigger nozzle should be more forgiving in regards to filament as well and not clog up as easily.

I got an e-mail yesterday that it has been shipped so back to playing the waiting game...

(Print)head in the right direction

While waiting for the print head from qu-bd to arrive I tried out fastening the Sumpod print head directly to the new aluminum y-axis.

Seen from below

The thickness of the plate, at 3mm, wasn't exactly ideal since the bottom part of the peek wouldn't quite go deep enough to make contact with the aluminum nozzle. That left a gap which potentially could leave room for the PFTE tube to expand like last time. I solved this by winding teflon tape around the PFTE tube - which then went into the nozzle.

I also wound teflon tape around the base of the peek in effect stabilizing the nozzle and minimizing the contact between the nozzle and aluminum plate - to reduce heat transfer. That way the peek hopefully would stay as cool as possible.

Top view

I just about managed to finish this setup before the new print head arrived this Saturday. Unfortunately I didn't get to test it since I never got the extruder part working correctly. Given time that too would surely have worked - but no use spending time on that now.

Nice packaging

Assembly of the MBE Extruder v9 was straight forward following the assembly pictures and videos on their web site. The only step that was unclear was if there were any extra steps necessary to install the resistor - since they only show the heat cartridge installation.

Assembly done

Now I need to figure out how to fasten the new print head to the y-axis. Could be a challenge since the base plate is a tiny bit too wide. I need to give it some thought.

On another note; we received our laser engraver/cutter at the office on Friday so now it should get a little bit easier to machine some parts.

40W CO2 laser from Full Spectrum

Print Head Dissection

My "successful-print-happiness" didn't last long as by the next print the print head went back to it's old behavior. Particularly not feeding enough plastic and as a result screwing up the print by ripping up what's already there.

Not exactly 100% fill anymore...

Figuring something must have gone wrong with the print head/nozzle I did a bit of reading on the SUMPOD forum and although I couldn't find anyone having issues with my exact configuration of the print head I found a couple of possible culprits. Time to take it apart and see if I were right.

Right away I discovered that the aluminum nozzle was loose and not tightly fastened to the peek anymore. My guess it's caused by the repeated heating and cooling of the print head. I think it's the MakerBot manual that states you need to heat the print head before tightening the screw so that's something to keep in mind.

The PTFE tube (below) has expanded quite a bit.

As you can see from the picture above the PTFE tube is no longer straight and has a bump where the gap between the nozzle and peek had a gap. Because of the expanded tube I had to cut it off before I could completely disassemble the print head. The brown stuff at the bottom of the nozzle is plastic from the print process (before I got everything tuned it was quite messy).

The inside of the tube has expanded as well and makes a reservoir where the plastic can bunch up. This is probably the main reason the flow of plastic isn't as good as it should be.

Underside of the print head holder showing the MDF fitting around the PEEK.

I also believe the filament get's too hot further away from the nozzle - which will possibly make it expand while still in the PTFE tube. The previously measured temperature on the fastener seems to indicate this. One of the reasons might be that the MDF has been routed in such a way that the PEEK is incapsulated and therefore not able to cool down as efficiently.

There's also quite a lot of surface connection between the PEEK and the aluminum increasing the heat transfer even more. One way to lessen this would be to let the nozzle screw into the PEEK instead of the other way around. As I don't have access to a lathe I won't be able to test that theory, but someone else hopefully might.

I've had to cut my bowden tube twice now the remaining part is to short to work leaving my print head out of business. Since I'm expecting a replacement head from QU-BD soon I figure I might just as well start preparing my printer. The "old" setup don't have room for the new print head so I'll have to remove the MDF and fabricate a new y-axis. I'm thinking using more aluminum (same as in the print bed), but we'll see. I'll also move the y-motor off the carriage to reduce the weight as much as possible.

Successful Print

A small followup to Fridays post. I've been doing more printing and the print head clogs up roughly at the same time every time with the result of a ruined print and needing to yank out the PLA. The increased value of the extrusion-multiplier had nothing (or very little at least) to do with it either. After a failed attempt I measuring the temperature on the push fitting to 60 degrees C! Too hot to touch.

Aluminum foil heat sinks.

I had a couple of small heat sinks, but no thermal compound and way of fastening them so I brought out a sheet of aluminum foil which I folded, cut and attached to the print head.

I also added a fan blowing air over the improvised cooling solution. Not pretty, but as a proof of concept more than good enough. Press "Print" and wait...

Roghly three hours later I had my result:

A little bit of cleanup needed, but apart from that very nice.

Pretty much perfect! The print head oozes a bit so there's small bits/balls of plastic here and there that needs to be cleaned up, but over all I'm very pleased with the result.

SUMPOD Heated Build Platform Part 2

I've been using the last week to put together "Heated Build Platform Mark II" consisting of aluminum sheet instead of glass. As I mentioned in my previous post I had an old Apple Pro cabinet where the side cover can be taken off easily. Being 3mm thick makes it perfect for this project.

Only negative thing was no access to a workshop or proper power tools...

I ended up using the non-metal wood hand saw.

Having read somewhere that it is possible to cut aluminum with blades meant for wood I though why not give it a try with my existing equipment.

Marked, taped and ready...

The saw was a cheapo so no big loss if it didn't work out - which it did :) I can't see any damage on the blade afterwards at least. Sawing aluminum this way is hard work so I won't recommend it if you have an alternative though.

New vs. old print bed.

Using the old platform as a template made it easier to drill holes in the right places etc. I made sure to tape the surface with masking tape first and to clamp the aluminum between two pieces of wood to avoid splinters. Sanded over all the edges with fine grit sanding paper afterwards.

Test fit.

Not shown here I made sure to test the heating functionality thoroughly before threading the wires and installing the platform.

Aluminum is a great heat-spreader, insuring pretty even temperature over the whole surface so that's great! Using a metal platform is not without it's drawbacks though. There's ample opportunity to electrocute yourself if you're not careful. Therefore I added two layers of Kapton to the underside before laying down the heat-wire. I might ground the plate at some point, but I'm not too worried since the platform will be warm when the power is on so I really don't want to touch it when it's active anyway.

The shielding on the wires I used are good up to 90C, which is more than enough for PLA, but If at some point I'm going to print ABS I probably have to rework that part.

Wired, levelled and ready for first print.

My second thermistor (RH16-4A104GB from MMC) worked out much better as well, being off by only one degree C. More than good enough for my purposes. I installed it roughly in the middle of the underside of the platform directly in contact with the aluminum and sealing the whole thing with Kapton.

Made sure there was enough wire to avoid it getting stuck or ripping anything loose.

Having made a few test prints there's no doubt the heated surface makes a huge difference in making the PLA stick to the surface. I haven't had one false start. That is, the plastic sticks on first try every time. I've had a couple of prints where very thin details becoming unstuck during the print, but for the most part it's been extremely good.

This time around I've been testing Slic3r which I like a lot for it's simplicity compared to Skeinforge - it's a lot faster as well being coded in C++. It seem to be a bit courser though. When it comes to fine detail and thin walls it sometimes leaves gaps, even when I have selected solid fill. That's something that I have to figure out.

The next issue to solve now is the feeder/printhead mechanism. I had the print head clog up three times the last couple of days and I'm still trying to figure out why. It seems to only happen on longer printruns and my initial guess is that there's a combination of several parts getting too hot. I've been playing around with increasing the filament extrusion-multiplier as well so there's a chance that's the reason. More testing needed :)

Just in case I ordered a new, and more compact, print head last night from QU-BD. Hopefully I will be able to use my existing Nema 17 stepper on this one. The bonus is that I eliminate the bowden tube and any slack in that type of setup. There is a disadvantage in moving more weight onto the y-axis so I'll have to test before saying anything for sure, but I might have to move the y-axis motor to the back of the printer frame and re-rig the belt.

So far I've been using the Sprinter firmware, but I think my next project will be to upgrade to Marlin since I've heard it's a bit better quality wise.

SUMPOD Heated Build Platform Retrofit

There's not been much progress on my 3D printer during the summer months since I haven't been much home, but this last week I've had a bit of progress.

Where I left off before summer showed I had some challenges to overcome with the build quality.

Failed prints

Mostly I've been playing around with the settings in Skeinforge - which is a hugely complex software for slicing up the 3D model and preparing the g-code for the printer. Using Airtrippers PLA settings as a starting point I got pretty good quality for the bottom and side walls, but the filling still gives me issues. As seen in the picture the print head tears up the fine inner walls in the model and produces big, gaping holes that the printer can't close when doing the top layer at the end.

I suspect this mainly is caused by to low flow of material on the interior walls, but I haven't been able to find the right setting to increase this yet. More testing needed. I might go back to scratch and test with coarser settings, i.e. thicker layers, to see if that helps as well since part of the problem is that the previous layer stick to the printer head.

Another, frustrating, issue is that the printer seems to print when moving from one position at one side of the model, to another at the other side. This leaves a slightly higher stripe of plastic that creates non uniform surface on the next layer. This can be seen particularly good at the center object on the bottom layer on the picture above. I don't think it has to do with residue plastic continuing to ooze from the print head since it seems to consistent for that - but I could always be wrong.

Getting the the print to stick to the build platform has also been challenging. At first I used the provided MDF platform with blue masking tape. Depending on the temperature in the room I had to restart the build 5-10 times before the PLA would stick properly. Increasing the temperature of the print head above 185 degrees C does not help with the brand of PLA I'm using at the moment. I've also played around with increasing/decreasing the distance between the print head and the build platform up until the point of the filament jamming.

Changing the build platform to use glass seem to help a bit - when heating the glass with a hair dryer directly before starting a print. Still takes quite a few tries to have it stick. Seems like the printer doesn't feed enough material at the beginning as well. I'm printing without a raft since I can't be bothered to remove it afterwards ;)

Glass picture frame from Clas Ohlson. Cheap at just over €1.

Still covering the glass with blue painters tape

Seeing heat was the way to go - a heated build platform was the next logical step. I ordered a huge (20 cm wide) roll of Kapton tape from e-bay to avoid having to overlap when covering the platform. Thinking Nicrome wire easy to source I didn't order any, but I couldn't be more wrong. This is one of those things that's really hard to get hold of here in Norway for some reason. After googling and trawling forums I finally found a substitute in a forum thread about styrofoam cutters; Kanthal wire. With nearly the same specs and even surpassing some - like handling very high heat - it seemed ideal.

Glass printer bed

Measuring the area the print head could cover was a bit disappointing. As can be seen from the picture above where I have cut the glass to match. Except for about 5mm extra on the left and right side that's about it (14x15cm). I had to cut one of the corners to make room for the leveling adjustment bolt.

Trying to keep the three wires (in parallel) at the same length of 460mm was a bit of a challenge since not all the traces would be identical in form.

I started by adding a layer of Kapton to the top layer of the glass plate and then proceeded to tape the Kanthal wire to the bottom with strips of Kapton.

Almost done, just need to fasten the wires to the power
source...

Using non-tempered glass, knowing full well that the glass probably would crack during repeated heating and cooling, I still had to try it out. Sourcing, and cutting, this kind of glass is another thing that's not easy to get done apparently. However; having the glass crack during assembly was a disappointment, but again  entirely my own fault being careless with a screwdriver.

I had to try heating it up anyway so I hooked up the (converted) PC power supply and turned on the juice. This taught me two things; first of all - the thermistor (temperature sensor) was the wrong type as it showed 20 degrees higher temperature than it actually was. Fortunately I have another thermistor (also rated at 100K) that I'll try next. Secondly I discovered that the heating was extremely effective - yay! I didn't time it, but it felt like between 10 and 15 seconds between I turned on the power and the platform measured 60 degrees (taken with my heat sensor gun). Not having to heat the whole print bed, but only the actual area needed, probably helped here. The glass also only has a thickness of 2mm. Hearing a loud crack made me turn of the power pretty darn quick though ;)

Side panel of an old G5 Mac Pro... use what you've got :)

So what's next? The Mac Pro cabinet is all aluminum and has an easy removable side panel with 3mm thickness. Adding one or two layers of Kapton tape to avoid a short - before adding the heating wire should make it quite ideal for my purposes. Bring on the hack saw! :)

SUMPOD Bed Leveling

I now have the final bed leveling mechanism assembled. This version is a lot easier to fine-tune than my first try. Another advantage is that it is pretty heat resistant so I can add a heated bed if and when I decide to.

Spring loaded action...

A big thanks to Mark Hindess for sending the parts needed!

SUMPOD Printing

This weekend I finally got to do a proper test-run on the SUMPOD (total printing time around 7-8 hours). After using most of last week to trouble shoot and figure out usable settings I stumbled upon Airtrippers excelled Skeinforge settings. Since he already has his SUMPOD up and running and having excellent results, from what I can see, at least I knew these were going to work.

After browsing Thingiverse a bit I ended up on the "Mustache Ring" for my first, proper, test. It has some nice detail and doesn't take too long to print so one can experiment a bit.

First proper test object. Mustache Ring.

If you look closely you can see that there are gaps and that the layers don't fill properly.

So far I haven't had any big issues getting the plastic to stick to the printer bed, but changing the filament and using the new Skeinforge settings apparently made a huge difference. All of a sudden it wouldn't stick at all. At first I though I needed to up the temperature in the print head, but that only made it worse. I also played around with the height of the nozzle over the print bed. Supposedly you should have the nozzle touch, or even press a bit into, the blue masking tape, but that just made the PLA bunch up around the print head. Reducing the temperature back to 185 degrees C in addition to increasing the distance a bit  did the trick - although now it almost stick too well and I have to rip the masking tape off of the bed on larger objects. I doubt that is right.

I soon realized I was going to need something to help unwind the filament from the spool since I can't go over and unwind a chunk every 15-20 minutes on multi-hour prints. Yet again Aitripper saved the day with his design for the Pocket Reel Roller. He also lists his settings for printing this, but I needed to change those around quite a bit before I had something passable.

Mainly I had to change "Speed -> Object First Layer" (all to 0.2) and "Fill -> Infill Solidity" (to 0.9). Print time was around 2.5 hours.

Third print of this part. 

With roller bearing installed.

Not exactly pretty, but I think it will do the job. The last part actually came out worse, but I think that's because the belts have gotten a bit of slack. I'll tighten them up a bit and hopefully that'll do the trick.

All installed - turns pretty easily as well.

I still has some way to go to get the quality up to the level I like, but playing around with the parameters in Skeinforge has a lot of potential - I only have to learn what causes what and that's not something that's done over night with the amount of parameters you have access to.

Alternative printer bed leveling

While I am waiting for the proper parts for leveling the print bed I came up with an alternative way. It's not something I would recommend if you have a heated print bed, but as I do not it's worth trying.

I found some packing foam and som IKEA cupboard bolts which should do the trick. The foam has the right springiness and by changing the size of the pieces you can get the proper resistance. Covering the whole back side of the bed was too much I found out.

Pink and stylish

Note the black drinking straws

Notice the four, black, drinking straws. These had the exact right diameter to match the predrilled holes and keeps everything nice and centered.

Before tightening of the bolts

First try. I found that since I had to tighten the rear bolts almost all the way the small pads of foam I started with weren't enough in the front.

After tightening of the rear side.

Added some more foam and the result turned out much better! Leveling took some time since tightening or loosening one screw affects the height of the nearby foam blocks so I had to re-measure and adjust the other bolts several times before it all was level. Still; I'm happy to be able to use the printer until I get some better parts.