The 3D Printer Thread

[Woz]

........... It is a minimum of 2.00mm........

RobG

Yikes no wonder you've had problems.

[wibblywobbly]

Whilst I await a response from the first filament company, I have searched the web for reliable suppliers. Have now ordered a 100m roll of 1.75mm. It came as no surprise that 1kg cost £14, but the 100m/ just ordered was £21?

Hopefully this will see an end to the problem. It would explain why it started off printing ok, and then clogged. The RichRap designer had a whole host of problems with filament, He even found ball bearings in a reel that he had from China??

http://richrap.blogspot.nl/2012/06/jamm ... -1518.html

This makes my issues pale into insignificance. Having explored numerous sites, it seems that getting hold of quality filament is now the biggest bugbear in the 3D world, you simply don't know what you are getting until it arrives, and if it is rubbish what do you do? Return it and pay the postage costs or write it off/sell it on?

[MK1 Nut]

With my Brothers now old MakerBot 3D Printer, we found the feeder was temperamental, so I resigned it for him. Nothing amazing, it was just that at the time they used a spring loaded nylon rod to direct the ABS filament into the heated nozzle. So I pointed off a new enclosure with steel roller bearings and that problem went away. I think these days they all use bearing in their guide, so this should no longer be an issue.

We use these guys for ABS Filament... http://www.cd-writer.com/catalog/3d-pri ... 10356.html
They seem good enough and not had any reason to complain, we could though have just been lucky.
With the PLA and for that matter the ABS it sometimes helps to keep the nozzle temperature down, although that can some times be a balancing act with the print speed.
Keep the filament feeder clean and check for little loose bits of plastic that can fall in there when changing the rolls. As you pull the old filament out it stretches and the fine tail can end up in the feeder, this causes the rod to slip and the nozzle block or print quality to suffer.
A lot of what we thought off as nozzle problems in the early days turned out to be feeder issues of one sort or another.

[Woz]

I get my PLA off ebay-

http://www.ebay.co.uk/itm/200955218773? ... EBIDX%3AIT

http://www.ebay.co.uk/itm/131182410741? ... EBIDX%3AIT

So far I've only had one jam and thats when I pushed it up to 120mm/s mid print (forgot to turn up the heat).

I have a Makerbot clone with a Mk9 extruder. The advantage with this type of extruder is that the feed motor is only a few cm's from the hot end, so the filament isn't being pushed through a long tube.

[wibblywobbly]

I will see what the stuff I have ordered today is like, at the end of the day I won't be using a huge amount of the stuff, so having a smaller quantity rather than a 1kg spool means that I don't end up with a load if here and having to concern myself with storage. Been reading up on that, and the moisture absorbtion can be dire.

Added those suppliers to my Ebay, future reference.

[RobW]

Not got any additional (pun intended) info as yet, but looks like Autodesk are releasing a freeware CAD code "Spark" for hobby level 3D printing. There was an article in one of the Manufacturing magazines I get sent.

[wibblywobbly]

I finally nailed the clogged hotend problem that was plaguing me, so if anyone else gets this problem here is what I did.

I am printing PLA, and around 185-190 degrees. While the printer was printing there was a cold feed of filament to the heater block, but when it stopped, and if the hotend was still hot/heated (which was usually the case while testing printing), the heat was travelling back up the filament inside the hotend and softening the filament right the way up through the Bowden clamp. Start printing again, and hard cold new filament pushes on soft warm filament, it deforms and forms a solid blockage.

(Why do they use a Bowden clamp? The print head is whizzing around while printing. The heavier the print head, the greater the mass and the inertia. Every time it stops and starts, the greater the weight, the greater the inertia. This causes accuracy problems, so the print speed is reduced. Using a lightweight Bowden tube, and a feed mechanism that is mounted on the base of the printer rather than a mechanical one that is mounted on the print head allows the print head to move at a much greater speed, and print more accurately).

So I ordered a metre of ptfe tube, and some spare Bowden clamps for good measure. I replaced the entire feed tube from the extruder hob bolt, and also cut off a new section to go inside the threaded part on the hotend. Bingo, silky smooth filament travel.

I ran the printer again, but of course, it printed ok, but when it cooled....back came the jam.

To remove the blockage (which was always at the top, the cold end and inside the Bowden clamp) I removed the ptfe tube and dropped it into a bowl of boiling water. This softens the PLA and allowed me to stretch out the blockage. Pushing a new piece of filament into the other end pushed the deformed PLA out. At least I can now remove a blockage without any fear of damaging the tube or the clamp.

Once I had confirmed that it was conducted heat travelling back up the filament that was causing the problem, I experimented with turning off the heat and manually pressing the extrude button on screen. I kept doing this until the stepper motor started to click, which was a sign that the heater had cooled down and was no longer melting the PLA. This meant that only fresh unmelted PLA was now in the bowden and hotend, and would not deform. By timing how long the hotend took to cool (it was at 150 degrees when it would stop extruding) I could then add Gcode to the end of the print so that the print head moved somewhere safe, and then just pushed out the molten PLA until the feed wasn't being melted anymore.

So that was that problem solved.

...at which point I realised that the hexagon test pieces that I printed when I originally tested the printer were A1 quality, but the prints that I was now doing weren't. The hatch was printed as one piece, which was quite demanding, but the finish is poor. The filament was coming out very narrow and getting worse, and had a serrated edge to it. I took the nozzle off, gave it the blowtorch treatment, but it was still the same. I ended up heating the damned thing so much that it deformed the threads. It seems that there is a hairline piece of swarf across the 0.4mm hole on the inside, and that was causing the rubbish print layers.

So, I am now ordering some new nozzles. I am tempted to buy an E3D hotend as they are reputedly the bees knees, but they are 'very' expensive, and so are nozzles etc. As with all things, you get what you pay for I suppose?

RobG

[Woz]

This looks interesting.-

http://carbon3d.com/

High detail at high speeds.

[wibblywobbly]

Not quite in the home budget just yet though. lol. I saw them on the Sky News website earlier, excellent technology but I bet that they cost an arm and leg.

I am awaiting two new nozzles for my hotend, I am pretty certain that the one that came fitted to the new hotend has some swarf inside the hole, plus I now have Cura ready to go, together with a config file that was done by the guy that sells the printers. I also discovered that I had forgotten to tighten two of the linear bearings in when I built the printer, and that there was a flaw in the design of the hatch that reduced the final layer thickness, so have redone the whole thing and split it out into three parts.

I am now hoping that when I can start printing again I will get the quaiity back that I had when I started out. The original test pieces that I did look injection moulded, they are really good , so fingers crossed.

[wibblywobbly]

At long last

New nozzle, and using Cura rather than Slicr, a few changes to the printer settings in Pronterface, and I am cooking on gas. This was printed at 130% speed (1 hour 50mins), I repeated it after the video at 150% and the finish was almost flawless.

I am a Happy Bunny now.