Annoying Bowden and hottip fix - Need skienforge help

Hello All,

Ive finally got my huxley to print a decent part. But to fix that I had to purchase a totally different type of hot tip, mentioned on the Below post. Also I had to put screws on each end of the bowden to ensure the cable doesnt release.

All in all, Im trying to print out a prusa as soon as I can before this huxley dies on me so I at least get my money's worth. I wasted 600$ with techzone.

Please dont make the same mistake I did...

Here is the post! [omemon.wordpress.com]

Anyone Who can help me make the screw holes nicer, please let me know which setting I should change in Skienforge. Also this print took 3 hours. Any way to increase the speed without giving up on the decent print? I notice it speeds up while filling, but while printing it is slower. Any tips?

Thanks all!

---

[omemon.wordpress.com]

oh i remember seeing one fellow who,put i think it was a m6 nut on the cable, he mentioned you had to drill it out after the nut squished it, but it should work. i found mine have a really good grip on my bowden cable i didnt need a nut or anything on mine.

---

[mike-mack.blogspot.com]

+1 Still haven't managed to get my huxley to print properly. I can't event get it to push the extrusion through the bloody tube without it striping. Considering getting guys at local hackerspace to just print me parts and build a prusa.

An expensive waste of time to date....

Steve

I think the cable (bowden tube) is too tight on the filament in techzone kits.
I've bought a 3.2 mm inner diameter one for replacement.
Not tested yet.

where is your jam with the cable, i have the same kit, but all my feed stock from ultimachine has been working great so far.but i also didnt use there hot end, i already had one from maker gear.

did you try drilling out your tube after you got it into the mount.?

i am not going to say i have got great results so far, but i am getting better has i learn what settings to use. i am using repsnapper though, i need to work on my setting for skeinforge still

---

[mike-mack.blogspot.com]

I can't comment on Techzones products other than to say a large portion of the problems people post about on the RepRap forums involve their products. Mendel, electronics, etc.

So either it is Techzone or the people who buy products from them expect to much. ( you bought it because it was cheap but expect Up quality out of the box )

I built a RepStrap Huxley and love it. (nothing from techzone) but it has been a huge learning curve and a lot of testing and tuning. 5lbs of PLA went into testing and printing none perfect parts. Another 5lbs has now gone into nice parts since.

I went through 3 hotend variations until I found one I was happy with. I've changed the firmware settings 20-30 times, made hundreds and hundreds of skeinforge changes.

So what I am trying to say is that ALL reprap derivatives are a LOT of work the first time you are learning. A lot of the issues you are having are simply part of learning, although some may be crappy products.Stop comparing your prints with those of the PRO's, be amazed you can print in 3D and start improving, fixing and tuning your machine.

Edited 1 time(s). Last edit at 06/29/2011 02:17PM by Sublime.

---

FFF Settings Calculator	Gcode post processors	Geometric Object Deposition Tool Blog
Tantillus.org	Mini Printable Lathe	How NOT to install a Pololu driver

Thanks Sublime for that. Your right about that. The only reason I complain is so that others do not purchase the same thing.

It is a great learning experience and Im loving every minute of it. Part of the learning experience is asking those who have done it before so that we don't have to go through it again.

My hot tip just clogged so here comes another new task . Besides torching it,(i dont have a torche) I heard I can just soke it in Acetone?

Any other techniques to clean up the clogged nozzle?

Thanks

Acetone will only work for ABS.

The only time I ever had jams was because the edge between the heater barrel and thermal barrier was not perfect.

Nophead describes the issue here
And he shows how serious it is in this video (notice no nozzle)

This is when I went with his design but made a latheless version. Instructions


I have found to un-jam it you just need to pull the filament out of the hotend while hot (backwards). This stretches out the plug that has formed. Another issue you may be having is that you have to much heat raising up the heater barrel and it eventually starts to melt the filament above the transition point which cause the same plug effect.

As for complaining I completely understand what you mean. I almost bought a Huxley from techzone, then I decided to build my entire machine from scratch. Then when my first arduino 168 based electronics failed I purchased the last RAMPS 1.2 available and it got lost in the mail, traveled more than 10,000 miles over a few months at which time I considered buying Techzone electronics before Ultimachine finally made more boards and was able to reship my order. I had not spent much time reading the RepRap forum before that point but now that I have I am glad I did not buy anything from Techzone, but wonder if things are really as bad as people make it out to be.

Edited 1 time(s). Last edit at 06/29/2011 02:13PM by Sublime.

---

FFF Settings Calculator	Gcode post processors	Geometric Object Deposition Tool Blog
Tantillus.org	Mini Printable Lathe	How NOT to install a Pololu driver

I think my jam was due to a faster extrusion speed. Im hypothesizing that the pushing was more than what my .5mm nozzle could handle. My feedrate is set at 13 and flow rate set at 20. Before when it was working fine it was set at 9 and 16.

Maybe because the plastic couldnt push out fast enough from the nozzle, this caused the melted plastic to move up the PTFE tube and go cold and jam.

What gap do you mean? The current setup I have right now is the following, but I removed the screws which hold the PEEK block because they were getting hot and making my carriage bend: [www.reprap.org]

I am using abs, so first I will try to pull it out while hot. I tried to pull already but at the extruder end of the bowden. I will cut the plastic and try to pull it directly out of the PTFE tube.

Thanks for your helps. Any more videos would be useful.

Oh and about Techzone products.

They support very well, but seeing that they know there are problems with their product and they aren't sending their parts already fixed with those solutions, that doesn't show professionalism. For example they know their hot tip will ooze out because of plastic oozing around the brass tip, they told me to put a wood screw in it. Now if that was the case, wouldn't they include a hole in the ptfe and a woodscrew? I had to purchase parts for this endeavor. I know this is DIY but when you purchase a kit.. kits are just 'unassembled' not un-finished product.

Anywho... I also like their monolithics board because it was a breeze to connect and looks nice and neat. Some people on the chat told me that it will die soon, but I'll report it on the general forum when it does...

Plastic parts were also a pain to deal with because it required me to drill holes, requiring me to purchase more tools. BUt thats what taught me so much and helps me put this on my resume .

I guess thats thanks to Techzone . I hope more companies can come out with better kits.

Ok I made a picture to explain the problem.

DO NOT take this as me saying the hotend pictured has this problem. I just used the picture on the page you linked.




Since you removed the part that is supposed to keep these two parts tightly together it could be causing the issue.

My method of preventing this in my design is to drill it out after assembly but before putting the tip on. I then heat it up and slowly run some filament through it by hand to clear out any possible debris left, then put the tip on. After that I have run 10lbs of PLA through it without issues.

Speed is not the issue. ABS can be extruded faster than PLA and I have videos on my Blog showing my Repstrap printing at 120mm/s in PLA. I have found the faster you go the higher the temp has to be to get the material to melt fast enough.

Edited 1 time(s). Last edit at 06/29/2011 09:53PM by Sublime.

---

FFF Settings Calculator	Gcode post processors	Geometric Object Deposition Tool Blog
Tantillus.org	Mini Printable Lathe	How NOT to install a Pololu driver

Every few weeks I get the motivation to look at this again but unfortunately after wasting another few hours with my latest idea to fix the bowden still no dice. I decided to cut down the extruder PLA tube to the maximum length I could successfully push filament through to. This seemed to work fine and thought I might actually be able to try and print.

Unfortunately with the shorter tube the lateral force on the X axis is just to much and it either loses steps or slips the belt.

So current options.

- Ditch huxley and move to prusa and try and bribe local hackerspace to print me parts. Should be able to re-use electronics and steppers.

- Stick with huxley print mini-extruder and get new hot end.

- Stick with bowden try a 3.2mm tube and a new hot end.


What do you guys think?
Steve

I stuck with my longer bowden tube. Your right about the lateral force.

my retraction is 25mm and I reduced the temperature to 190 after the first layer. I dont think its in reality 190, because the thermistor is not glass beaded and is hooked up to the aluminum block.

As long as I can get prints out of this huxley, im trying to print a prusa asap and then transfer my hot tip onto it.

I also have a very shakey y axis bed so I need to look into it.

I guess thats the fun of this project, theres always room for improvement. Rock on!

In case you got problems with ooze by the bowden extruder, you might consider two modifications I did to SF41.

The first is in cool.py as I discovered that this slows down the travel feed rate as well which gives time for ooze. So I fixed this.

Second I changed dimension.py, because I think it is better, if retraction only takes place in cases of >5mm travel distance.

I am very satisfied with the results on my Huxley.

You may find both files I altered enclosed.

Wow, theodleif, the dimension change is just what I was hoping for! I'll try it this evening. I gave up using cool as I had ooze problems, and tend to just blow on a part to cool it if it's a small column building up (the peak of the hollow pyramid [www.thingiverse.com] is a particular problem), but perhaps I'll give your cool.py a go as well.
Have you sent them to the Skeinforge developer to roll in with the next version?

Did you try it?

Yes, I tried your Dimension.py and it works very well. Excellent job! There are still quite a lot of retractions, I think the distance could be pushed up a bit higher, perhaps to 10mm. Is this easy to do? Or could an option be added to allow the user to enter their own value in the GUI? I've never looked at a Python script. But good work!

I also think Skeinforge could be smarter about optimising the tool path for a layer; it seems unable to change the direction of a tool path segment, even when the benefit would be a shorter move. Or maybe I'm not understanding the current optimisation, or it's not an issue for most reprapers as their moves aren't accompanied by a retraction. But I'm no programmer, so it will always be pure speculation on my part.

droftarts Wrote:
-------------------------------------------------------
> Yes, I tried your Dimension.py and it works very
> well. Excellent job! There are still quite a lot
> of retractions, I think the distance could be
> pushed up a bit higher, perhaps to 10mm. Is this
> easy to do?

Just change line 162 in dimension.py from

self.minimumDistanceForRetraction = 5.0

to

self.minimumDistanceForRetraction = 10.0

and try out.

Don't you get strings over gaps less than 10mm then?

---

[www.hydraraptor.blogspot.com]

nophead Wrote:
-------------------------------------------------------
> Don't you get strings over gaps less than 10mm then?

Might do, but it's worth experimenting. It's a toss up between strings or blobs for Bowden cables. I'll be glad when I finish my Prusa and get rid of the thing!

Quote
It's a toss up between strings or blobs for Bowden cables. I'll be glad when I finish my Prusa and get rid of the thing!

ditto!

The bowden extruder has its limits. No software will make it go beyond.

I guess, if there isn't a real alternative to the bowden extruder, the Huxley will be a dead end.

Jean-Marc claims the eMaker Huxley prints as well as the UP printer and that uses a Bowden extruder.

---

[www.hydraraptor.blogspot.com]

E maker doesnt seem to be selling huxleys anymore as I can't find that on their site.

Does Jean - Marc have a blog?

owism8 Wrote:
-------------------------------------------------------
> E maker doesnt seem to be selling huxleys anymore
> as I can't find that on their site.

Really? This is updated 5 days ago.

His blog is here: [www.emakershop.com]

Edited 1 time(s). Last edit at 07/22/2011 02:53AM by nophead.

---

[www.hydraraptor.blogspot.com]

Thanks. but hes not selling those anymore since they are not in the store.

I'll ask him about how he got the bowden to work so well.

owism8 Wrote:
-------------------------------------------------------
> I'll ask him about how he got the bowden to work so well.

I was thinking that. It would be great to know!

>> I'll ask him about how he got the bowden to work so well.

>I was thinking that. It would be great to know!


I'm not sure what E Maker did. But, I replaced the cable that shipped with my TechZone Huxley kit with a harder one. It has less friction and it is also less springy. I haven't had any troubles since. I'm getting fairly good and consistent prints. Now, I just have to learn how to make adjustments in the software.

Yeah youll find that your detractions will go up around the 20 to 30 range so thats fairly normal. I also have a TZ huxley and still am using the same cable.