RepRap Prescription

#RepRap Adventures #14 - When is it my turn?

2012-02-14T04:56:00.000-08:00

Click for lower resolution.

Things take an unexpected turn!

Make sure to follow this storyline from the beginning, then perhaps it makes a bit more sense.

Disclaimer: I have not tried printed bushings myself, and I hear they can hold up for quite a while if printed strong and used properly. Still, I prefer LM8UU's. ;)

You can print your own ponies with thing 6123.

#RepRap Adventures #13 - Why not print her a few?

2012-02-07T05:23:00.000-08:00

No less than 480000 pixels if you click.

They're back! This is the beginning of a small story arch I have planned for a while. There is no schedule for release, but I'll post them as soon as I finish a new one.

Tutorial - Printing from Minecraft with Mineways

2012-01-05T07:08:00.000-08:00

Mineways.com has been getting a lot of well deserved attention lately. In short it's an excellent Minecraft export tool, tailored towards Shapeways printing. While us DIY enthusiasts can't do full colour prints (yet), Mineways is still an excellent tool for exporting models for home 3D printing, and it's quite user friendly compared to certain other attempts.

Here's a few videos where I show my first attempt to do a large print of a landscape, and then a smaller print. If you have some experience with WorldEdit and 3D printing, it should be pretty straight forward to follow.

This post is a detailed tutorial on how to use Mineways to export printable stl files for a RepRap or derivative machines. The details are from a large-ish landscape model, but the principle is the same for all types of exports.

Here's the steps we're going through:

Prepare area to export in Minecraft, with the help of WorldEdit.
Use Mineways and export from a local world file to .obj.
Review and export to .stl with Wings3d.
Genretate gcode with slic3r.
Final result.
Exporting from online multiplayer?

Now for more details.

Update 01.06.2012: Fixed the scaling problem with help from Eric.
Update 01.07.2012: Fixed some of the abundant spelling errors, and added a video with a smaller object printed at 1block=1cm.
Update 01.08.2012: Added info on the new scaling factor from v1.06.

1. Prepare for export in Minecraft

While SLS printers have built in support and colours, and their commercial software might import all sorts of damaged stl files, our software is a bit more picky. On the other hand we can print huge (or small) models for a mere fraction of the cost! After a lot of trial and error I find the sure-fire way is to prepare the model ingame before export. For small buildings it's just a matter to build it so it's printable, and support structure in skeinforge could be of great help here. I haven't tried this yet though, so please comment if you do.

If you're going to print a larger landscape like I did in the video though, you really need a tool like WorldEdit (the link takes you to single player commands, which includes WorldEdit). Mineways only work if you have direct access to the world file, so this is all done locally in single player. Jump to step 6 for how to export from a server.

As you can see in the video I alter the world in a few ways. I won't go into detail with how to use it, but if you haven't used WorldEdit before, please be careful so you don't mess up your entire world! Backup is essential here! I take no responsibility when you trash your kids masterpiece and crash your server.

The red wool makes for a solid ground plane, do this first.
By replacing all blocks with gravel, you ensure there are no pockets of air in the model. Though if there are a lot of tunnels, this does cost you detail and definition of the landscape. It's the simplest way to make a manifold model without any overhangs though. With a larger selection it does lag a bit, in case you didn't notice.
Use //smooth, or //brush smooth 6 to remove any jagged edges.
Now we know there's no hidden tunnels, unwanted overhangs or bad geometry in the model, and we can go back and tweak the landscape or build other structures.

Preview the print by changing to your filament colour.

2. Export to .obj with Mineways

For this step you just need to download and start up Mineways. There's a nice detailed tutorial on that page on how to use it, including videos. Much of it doesn't apply to us though, if we do the proper work ingame first.

Now, why not export directly to .stl you ask? At first I had some trouble with the scaling, until Eric himself explained that Mineways by default exports stl in metre scale. As of Mineways 1.06, there is now a "Model's units" dropbox. We'd like to set it to millimetres, and then use "Make each block X mm high" to set the scale; set it to 10mm and each block will be 1cm when printed, and so forth. For the printed landscape I used 1block=1mm.

I still like to use wings3d to review the mesh first, but it's not really needed with simple exports. It does makes it possible to do some edits that are difficult/impossible to do in Minecraft though.

Here's a few screenshots from mineways, notice the red wool is clearly visible. When you right-click to select, be sure to start at the red wool as it sets the bottom height to export from.

Now where was I...

All ready to go.

When you have marked the correct area, select "Save Model for 3D printing" and choose "Wavefront Obj, without material preview (*.obj)" as the filetype. There's a few settings that are of interest to us, and are different from the defaults (v1.04).

Export no materials (we don't need those).
'Make Z up' not checked.
'Connect parts sharing an edge', 'connect corner tips' and 'weld all shared edges'. All checked.
'Hollow out bottom of model' not checked.

The export dialogue I used.

3. Preview and export to .stl with Wings3D

There's a lot of different 3D programs that would do this, I chose Wings3D as it imports .obj and export .stl natively, while handling huge dense meshes without a hitch. The .stl export for large files is slow though. Please comment if you made this work with a different program, like Blender.

I you want to change the scale, you can do it at this stage like I did. As you see in the screenshot below, my imported model was 1.37 wings unit across. That would make the model 1.37mm wide, which is yet a bit too small for the average DIY printer.

Notice the size. A bit small, no?

Select the model and scale it by the amount you want. Optimally you'd scale the model so each block suits your slicing layer height, but it's not noticeable on the scale I printed this.

Now, that's better.

One thing I didn't do, and that could've saved some print time, was to manual hollow out some of the big middle bits. In a mesh modeller you are not bound by the square building blocks, and can make all sort of support structures. I'll do some more tests of this in the future, but with custom made snap-off support we can print anything.

Export the file to .stl. Notice this will make Wings3D seem to hang, but as long as there's memory activity in task manager it should be good. I didn't time it, but I'm guessing it took about 10 minutes to export a file this big.

4. Generate gcode with Slic3r

I'm sure you've heard about the excellent gcode generator Slic3r, and I can't recommend it highly enough. Sure it will take a few days of tinkering to get to know it, but once you do it's a perfectly good alternative to sfact/skeinforge. And it's fast, super fast. A 5MB file in under 3 minutes you say? Yes, yes it can.

I don't even want to think about how long skeinforge would take.

I've included some screenshots of my settings, though they are very much machine and model dependent. I'm using an Arcol 0.35mm hot end and Marlin firmware. I normally print at 160-170C, but bumped it up to 190C as it's a huge, long print. The top did suffer and melt a bit though.

Because the Minecraft world is explicable to come with a lot of 90 degree angles, and because of acceleration, the full perimeter speed is only reached on the straights. Where you really catch up on speed on this type of model is the infill, and you might be better off turning the perimeter speed down if your scale is this small.

Some settings.

More settings.

Be sure to preview the gcode before you print. Pronterface is an excellent choice, and it also comes with a good estimate on time and filament used.

0.2 infill works fine for this size of model.

The y size is wrong, but the print duration was close.

5. Final result

Here's the 14x8.5x6cm result after 3h 55m. The printer behaved perfectly and didn't miss a single step once. The print weighs in at 105grams, and with the cost of 25-30$/kg I paid, would total at less than ~3$. Not bad compared to Shapeway prices, no?

You can see the individual blocks, though they are a bit rounded off, which is natural at this size. One block is 1mm wide on the model, but single block have swelled a bit and are closer to ~1.2-1.5mm in reality.

A bit difficult to photograph this semi-translucent PLA.

That's a nice world you've got there.... No really, I like it.

You can find the model on thingiverse if you want to have a look at it. The creeper keychain is also shared.

6. Exporting from online multiplayer?

Now, I'm sure you are as amazed as me about the creativity people show in Minecraft. On the server I play on the amount of awesome buildings is utterly insane. It's Norwegian only, though feel free to drop by to say hello and have a look around at hw.minecraft.no.

What I wanted was to print some of these works of art. The problem with Mineways is you can only export from a local world, thus you can't use it online unless you're an admin with full root access to the server. The idea behind my export script was based on schematic files saved with WorldEdit, as the server admins would only need to send over a single small file. And as a bonus you wouldn't have to mess around locating the area to print in Mineways, which would be quite cumbersome on our 12000x12000 map.

While Mineways doesn't import schematics (yet?), there is a simple workaround. You need to run a bukkit server with WorldEdit for this to work. If you host a server, you ought to be able to figure out installation by yourself. ;-)

Select the area online with WorldEdit and save it to schematic.
Fish out schematic file from server folder.
Copy schematic file to local folder. ("%appdata%/.minecraft/schematics" on Win7)
Load and paste the schematic into a local world.
Use Mineways to export, as per the instructions above.

That's it for now, hope it was of some use to you. Feel free to comment and ask any questions you might have.

Watch this spot for more Minecraft related RepRap printing.

-Nudel

PLA Review - Supply3DPLA Autumn 2011 batch

2011-12-26T12:04:00.000-08:00

A bit flimsy, but overall good spools.

My Prusa Mendel is really proving itself, and have worked reliable for quite some time now. Having a reliable printer means it eats filament like a hungry hippo, and it was time to stock up. Since I have previous good experience with Supply3DPLA, I wanted to try the colours in the new PLA batch they got in this autumn (was it october/november?).

This post is rather long, so I'll try a jump-cut...

Shipping

FedEx is now their main shipping partner, and it's a great improvement. The order was placed late on Thursday December 15., and I received it December 18.! Granted I was a bit lucky as they ship on Fridays, but it's still very efficient to ship next day. In total I paid €63 (~$82) for shipping to Norway, which is a great deal considering the package weighed over 12kg, and was delivered in 3 days straight to my front door.

Both thumbs up and a big smile from me!

Price

I ordered one 2.5kg spool of each of their new 3mm filament, green, yellow and red. I also ordered a 5kg spool of the red PLA from last batch, since I knew that was high quality, and it was even cheaper.

The small spools was €39 each, and the large 5kg spool was only €49. Since you don't pay EU vat in Norway the total including shipping was €195. I have yet to receive the tax paperwork from FedEx, but including local tax I guess it'll be ~€260. This sums up - for the whole order - a price per kg of €21 (~$27) (!), which is very, very good. Now let's see if the quality holds up.

Packaging/Spooling

The filament came in a big box filled up with packing peanuts, all the spools was individually sealed in saran wrap, and all but the big one was in a plastic bag with a moisture absorbing bag in it. The 2.5kg packages are pre-spooled, and since they are so cheap I was a bit worried if it would come off without tangling, but I've had no problems so far.

The filament on the red spool seems to stick to itself quite a bit though, almost as if it was moved onto the spool while being too hot. So I'll update the review if it turns out to be a problem.

Update Jan.03.2012: The problem got worse as I used more of the spool, and about half way through it sticks very much to itself, the diameter is uneven and oval, and it seems to be more brittle and snaps off from time to time. It still manages to peel itself off the spool relatively good though, perhaps due to the ptfe tube I use? The print quality have dropped a little bit because of this, but it's not a huge issue. I've contacted Supply3DLA, and they are looking into it. Many other customers have reported they have no problems.

No bearing works fine so far.

You can find this simple spool spacer at thingiverse.

I have previously considered spools an expensive luxury, but it's incredibly handy. Everybody who have tried fighting a big spool of unruly filament, can attest it's not fun at all. The 5kg coil was not spooled, but I knew that, and it was so much cheaper anyway, so I can't complain. A coil this big is pretty difficult to handle though, and you would want to spool it onto something to avoid a terrible headache. It's a bit of a chore to do by yourself, so it's easier to get someone to help you.

The big 5kg coil is not spooled.

Colours

Now onto the good part, how does it look? It's a bit difficult to to get the exact colour photographed, so I have slightly tweaked the brightness and contrast to get closer to how it looks in real life.

Green
The colour is describe as "jade green", which is a good match. It's slightly glossy and not fully opaque, it looks good, but is nothing special. The diameter is pretty consistent between 2.75-2.8mm.

The printed models are my parametric tie, and my minecraft creeper.

You use this where?

Yellow
The yellow is clean and crisp, it's glossy, just slightly transparent and looks great. I measured the diameter to range between 2.8-2.9mm.

The printed model is my super heavy duty OpenSCAD variant of this great spool. I'll post it to thingiverse when it's ready for prime time. Please note I printed this at 150mm/s perimeter and 180mm/s infill to test the limits of my printer, so it's function over form. On a side note I now print at 120mm/s perimeter and 160mm/s infill, as my hot end couldn't quite keep up with the higher speeds.

Fully printable spools ftw!

Red
Now this is it, this colour is awesome! It a very deep, burgundy, vibrant blood red, it's quite glossy, and pretty spectacular. The first lengths of filament has an average diameter of about 2.65-2.75mm.

I highly recommend this colour. It looks especially incredible against black filament, and a black extruder body with red gears would look great on any RepRap.

The printed models are the Prusa Mendel bar clamp, my minecraft creeper, and the spindle from the spool mentioned above.

I'm all smiles!

Old "Red"
See my previous review for a description. I measured it to be pretty consistent around 2.9-3mm.

I'm printing with this filament as we speak, and so far it looks like it behaves just like last time. It's very good, though it does look a bit dull next to the other red PLA.

Temperature and behaviour

The filament is quite soft and bendable, but it does snap if you bend it too much, or if it sits under tension for a while. It also has some kinks and bends in it, though this has not made any difference for me.

All the colours extrude fine at 160C through my 0.35mm Arcol v3 hot end, though the green one seems to flow more consistent at 180C+. I've been pushing the speed limit of my printer lately and I've had to up the temperature so the hot end can keep up. When printing infill at 150mm/s or above, I set the temp to 195C, and it's very stable. The filament doesn't boil, smell bad or get discoloured at all. I haven't noticed any bubbles.

I've had trouble with it on a couple of occasions though. If I let the printer stand idle with the heater on, the heat creeps up the filament and deforms it right where the idler wheel on the extruder pushes it against the hobbed bolt. When that happens it'll form a flat spot which jams itself in the cold end, and I have to take off the hot end to unclog it. I don't know if this is because of the hot end design, too high heat, inadequate cooling or too much idler pressure. But since it's never happened before, and this PLA is softer and more bendable than others I have tried lately, it just might be an issue with the filament.

Bottom line
Once again, Supply3DPLA has proven to sell high quality filament. I hear many people bash Chinese filament in general, but I can't see why. I can honestly say this latest batch of Chinese PLA from Supply3DPLA is amongst the best filament I've used. It's easy to work with and looks great, all at a very affordable price.

This PLA from Supply3DPLA gets the highest recommendations from me.

Nice, vibrant colours.

What's next?

Supply3DPLA is getting even more new colours in a month or so, and depending on how much filament I've got left, I just might try them out. I also recently got two small coils of awesome filament from Vik Olliver at Diamond Age Solutions in New Zealand, so I'll write up a review of that when I've tried it a bit more. And just this morning I got a package from faberdashery, with a whole range of nice colours to try out.

Two examples of the many colours Diamond Age supplies.

Faberdashery also have a wide range of funky colours.

I'll keep you posted as I get more experience with different suppliers. Take care! :)

-Nudel

#RepRap Adventures #12 - Still "extruding"

2011-11-04T12:00:00.000-07:00

*Insert joke*

Poop jokes? Always funny!

The joke came to life during a discussion in #reprap at freenode IRC, with a special thanks to digiFAB.
<digiFAB> Nudel: Sounds like it could be a good comic strip

#RepRap Adventures #11 - We beat you to what?

2011-10-31T16:25:00.000-07:00

Click if you like pixels in large quantity.

A "I was thinking of making a printable makerbot, but I see you guys beat me to it"-line, has been heard from a google engineer. True story! [Who cares about citations?]

#RepRap Adventures #10 - Let me tell you one thing!

2011-10-19T07:34:00.000-07:00

1200x400 resolution available for clickers

The rip-off line has actually been heard, true story! [citation needed]

RepRap-cat wants YOU to build a RepRap

2011-10-12T10:20:00.000-07:00

I was just playing around in inkscape today, and came up with these. Click for 1920x1200 resolution.

In case you don't understand any of this, check out this video. It won't explain it though.

#RepRap Adventures #09 - Doing it properly

2011-10-02T15:45:00.000-07:00

Click to view larger pixels.

Based on a true story!

With this, my backlog is used up, so #RepRap Adventures will now be posted whenever I draw one.

Feel free to comment with your ideas for how to continue this story. :-)

#RepRap Adventures #08 - We're living in the future

2011-09-26T02:58:00.001-07:00

Size full? Click

#RepRap Adventures #07 - Practical application

2011-09-19T03:20:00.000-07:00

Full click for size

#RepRap Adventures #06 - Only the best thing ever!

2011-09-12T04:27:00.000-07:00

Click for full size

#RepRap Adventures #05 - La révolution!

2011-09-05T04:08:00.000-07:00

Click for full size.

It's back! In colour, of all things. I have a few strips with an ongoing story lined up, so expect a new one on Mondays, until I run out of ideas and/or time.

New Prusa snap fit x-ends not fit for PLA?

2011-07-10T15:17:00.000-07:00

I just printed the new snap fit Prusa x ends, and ran into a few problems.

The red highlights are where the part cracked under stress. First from inserting the smooth rods, then along the holes for the zip tie, when I pushed in the top lm8uu bearing.

Print settings

This is printed in white PLA from Ultimachine @200 deg C. Nozzle is 0.5mm, layer height is 0.35mm, it has 2 extra shells (thus 3 in total) and infill of 30%. I believe the problem is the flexible part of the push fit design, which doesn't flex at all. I don't know whether it's because of the brittle PLA, or if it can be avoided by using either fewer or more outer shells. Heating the part before inserting the smooth rod will probably help, but

If this is a problem with PLA, I hope there will be an option to switch out the push fit with m3 nut and bolt. Looking forward to having a look at the OpenSCAD files!

Blame the user
The crack along the lm8uu holders is most probably my own fault, it was a tight fit, and I did manhandle the bearing quite a bit. There are some small lips to hold the bearing in place (in the z direction) and the bridge did sag a tad so the bearings didn't fit very well under the top ones. You can sort of see it in the second picture. Using 100% infill might solve this, as moving the holes up would just move the weak spot.

Edit 2011.07.11 :
I just printed the x-end idler, and the bearing holder snapped when I pushed in the bearing (had to use a wood clamp, it was that tight). This trouble might be my printer drawing outside of the lines, instead of on the inside. I'll be back with more info.

Difference in PLA?
This is the first object I have printed in this white PLA, and it might need a little skeinforge tweaking to get perfect. It seems to flow more, and thus pushes out more plastic than with the other Ultimachine PLA I have. (Silver, transulent blue, natural and black).

For this print I tried to drop the speed from 60 to 55mm/s, and on the x ends, it didn't loose enough y-steps to ruin the results. I have a theory it might be the weight of the plastic spool keeping the maching from rattling, anyone else experienced this? I still can't print gregs lm8uu x-carriage properly though.

New hot end review on the way

While I'm blogging, I might as well drop in a picture of a nice little puzzle I got in the mail:

It's an Arcol 0.35mm hot end, which I'm looking forward to try out. One thing I'm a sceptical about is the hot end relying on threaded PEEK to hold the pressure. People have a lot of good of things to say about this design, but to me a push-fit version just seems a the "safe" way to go. Also, it's a bit large to fit on gregs lm8uu x-carriage, so I have to figure out which printer to put it on, as it won't fit on Adesina now.

#RepRap Adventures #04

2011-06-21T04:17:00.000-07:00

Click for full size.

My biggest print yet, and it's creepier than I thought it would be.

2011-06-16T07:16:00.000-07:00

I've always wanted to print one of these, and when a simple straight-to-skeinforge-version with non-broken stl files was posted by RoTorIT - http://www.thingiverse.com/thing:9321 - I had no excuses any more. Thanks a lot. :)

The body piece is 22cm across, and printed diagonally it took every single mm of bed space I have available, which turns out to be 170x185mm. I even had to turn off skirt to make it fit, and it came dangerously close to the bolt heads on the bed. But it was totally worth it. the spider is HUGE.

Total print time was close to 24 hours @55mm/s. I had to print one piece at a time, because for some bizarre unknown reason I lose y steps if I print several objects at the same time. Some of the pieces are the same, and I'll post them here for your enjoyment:

Part 6 & 7
Part 8 & 9
Part 20, 22, 24, 26 (small leg)
Part 21, 23, 25, 27 (large leg)

The pieces doesn't fit together that well, and could have been 0.5mm fatter. Though both the mouth parts and tail parts sits tight amongst each piece and locks itself in place, the legs sit quite loose. I sort of solved it by squeezing / bending the print a bit while hot off the printer, which made most of it sit pretty nice.

In case you didn't notice already, it's printed in transculent blue PLA from Ultimachine, which is UV reactive. It looked far less scary when I took the pictures last night.

Imagine this scenario: You place the spider in a dark corner of the basement, with the room lit only by a single bulb. Then you hook up a motion detector which turns off the bulb and turns on several UV leds pointed at the spider. I'd do it, but it'll probably be smashed to pieces in blind arachnophobia fear, and I really don't feel like printing another one (before I have a giant bot farm).

#RepRap Adventures #03

2011-06-16T06:00:00.000-07:00


Click for full size.

True story! Read it here.

#RepRap Adventures #02

2011-06-14T04:30:00.000-07:00

Click for full size.

#RepRap Adventures #01

2011-06-12T09:50:00.000-07:00

Click for full size.

True story!

Post your ideas/stories in the comments, and we'll see if something happens. :-)

PLA Review - supply3dpla.com

2011-05-27T07:49:00.000-07:00

More filament suppliers is always a good thing, even more so when they are shipping from a location near you. After seeing a small advertisement on the RepRap forums, I chose to try out the PLA from supply3dpla.com who are located in Sweden.

First, the postal service managed to ship my package to Denmark, but Bo was very forthcoming, and shipped the package again. Total shipping time to Norway was 6 days, including a 4 days (unnecessary I might add) delay at customs. If you live in Norway (and outside the EU?), you can ask for the VAT to be removed, shaving a few € off the total price.

I ordered 400g of both the red and the blue, and got some samples of the transparent and black color as well. These are the only colors they supply at the moment, but Bo told me they plan to supply both green and yellow, and perhaps ABS.

How is the quality?

All the filament is "soft/smooth" to the touch, and feels quite bendable and "fresh". The diameter was a pretty consistent 2.88mm-3mm, and a bit oval. I forgot to compensate for this in Skeinforge 41 - dimensions, but the prints are looking very good, though it spit out a tad too much plastic now and then.

The PLA extrudes very easily at 185deg c, not needing a lot of tension on the extruder. All colors behave the same, as far as my small testing goes. It also stick very, very well to the heated build plate with glass @40 deg. So well in fact, that I pretty much have to clean with acetone after each build to get the stuff off.

What does it look like?

The colors are difficult to describe, as they are not a "pure" color, but rather a mix between several. I'll try my best with photos in different light conditions.

The "red"

In filament form it's very transparent, and looks delicious. When extruding it's almost completely transparent, and you need a couple of layers to really see the color. The final color is a kind of mix between red, orange and pink. I was hesitant at first, but the color is growing on me.

The "blue"

Just like the red, it's very transparent, and the same behaviour apply. The color is kind of "off" for me personally. It's like a strange mixture between light blue and cyan, and doesn't "pop" like the red one does. I might change my mind, but I doubt it. No UV-reactive goodness either.

The natural

In filament form it's almost 100% transparent, when extruded it's still pretty much transparent. In natural light it gets a bit of a yellow tint, but when you shine a led torch on it, it's quite nice and clear.

Most suppliers sell natural filament cheaper than coloured, but not here. It might be for you if you are incorporating lights in a model, but otherwise I'd go for something more funky.

The Black

This one is nice. It's a very deep, shiny completely opaque black filament. I thought the filament I have from ultimachine was black, but there is a slight difference when comparing side to side. It's difficult to catch it on camera though. Note: The filament I have from ultimachine has been laying around for more than a year, so I don't know how it compares to what they supply now.

Bottom line

The filament they supply is excellent! I'm definitely getting more of both the red and the black filament from supply3dpla. I don't know how easy it is to handle the big 5kg rolls of filament they ship, which might be a downside.

A nice little bunch with 6.8kg of filament from ultimachine just went through customs, so expect a review and comparison of that later on.

-Nudel

Tips & Tricks - Tape & Layer thickness

2011-05-20T02:56:00.000-07:00

Introducing RepRap Tips & Tricks, short blogposts where I share some of the small things you learn when you have a RepRap.

Don't tape your PLA filament together! When you're battling with a noncooperative spool of tangled filament, it might seem like a good idea at the time. When you have to degrease the tape residue off 2kg of PLA filament to avoid clogging the extruder, not so much.

If you have problems printing at high speed because the layer won't stick to the previous, try lowering the layer thickness under carve in Skeinforge (41). I went from 0.4mm to 0.35mm, and have done near-perfect gears at more than 50% speed increase from before. (Went from 20mm/sec to 33mm/sec).

Mendel-parts.com - v6 hot end first impressions

2011-05-09T03:06:00.000-07:00

I've been using the v6 hot end from mendel-parts.com for a couple of days now, and although that is not enough time to do a complete review, I would like to share a few things I've learned.

It's working beautifully! I always thought the hardware was to blame for my sub-par print quality, but with a proper hot end and skeinforge 41, I was able to spot the hardware problems. A new belt on the x-axis and metal gears on x and y axis did the trick.
I (and I'm not alone) needed to glue the PTFE tube/liner to the brass part to avoid it forming a blob which clogged up the whole thing. I did it by roughing up the surface of the PTFE and the inside of the heater barrel, and put on a very small amount of thermal glue. Take care not to clog the barrel! It seems to be working out nicely. Here's a picture after the first failed attempt at attaching it to a wades. The mounting bracket failed, and both the PTFE and PEEK pushed out of the barrel, resulting in all sorts of funky cleanups.

I don't like to glue the thermistor in place. Both because it would be impossible to remove, and because the thermistor I have from ultimachine is too big to fit. I could of course use the thermistor supplied with the hot end, but then I would have to change the temperature table which is not readly available. Anyway, I went with my decision of attaching the thermistor to a ring terminal and replace the copper ring with it. It worked out fine, but the temperature was WAY off. Because I use to weak springs on Adrians extruder, I had to increase the temperature to 205 degrees to get proper extrusion. After a while it clogged up and I found this inside the barrel. (Be warned, it's not pretty).

I now extrude at 180-185 and it works beautifully, I think I could go lower still.
EDIT: I have a theory the gunk was bits of PLA the extruder grinded off the filament, and not necessarily the temperature.

I didn't damage anything apart from breaking off the filament guide off "driven-holder.stl". Here I'm printing a new "idler-holder.stl" to have a spare.

To sum it up:

The mendel-parts v6 hot end works great!
Glue the PTFE tube to the barrel (carefully).
Use strong springs on Adrians extruder.
Test your temperatures with natural PLA to check for discolouring.
Skeinforge 41 with volumetric 5d is incredible! (Don't waste your time slicing with the old repsnapper windows build that's available).
When you turn off the machine, leave the plastic inside. I had no problems extruding straight away when heating it up again. If you pull it out it will most likely form a plug.

Update 01.02.2012: I've used the v6 hot end for a long time, and it's decent. Though because the melt chamber is so large it drools a lot, and the filament lingers a long time when changing colours. The Arcol v3 and J-heads (and others?) has no such melt chamber, only a straight path to the nozzle, which I find is a better solution. This is written only for completeness sake, as the v6 is no longer sold. Though the v9 looks similar, I have not seen it in person and don't know how it performs.

Well.. I'm off to figure out why skeinforge 41 sometimes decides to home during a print. It's no problem when it homes towards the endstop, then it just goes back to printing. The problem is when it anti-homes away from the endstop, trying to push the x carriage or the bed off the bars. I could attach endstops there probably, but that's just circumventing the problem.

Edit: Oh, and I made a funny Minecraft Creeper Keychain, check it out.

-Nudel

Inkscape to OpenSCAD dxf tutorial

2011-05-04T07:13:00.000-07:00

As some people are having problems with this, I present a small tutorial, as I believe I have found both an explanation and a solution. Inkscape is a wonderful program, and teamed up with OpenSCAD it makes a lot of cool stuff possible.

It works with Inkscape 0.47 and 0.48 without no extra plugins.

If you don't want to read my ramblings, the trick is easy: Make all the curved segments lines before you export to dxf.

Now, commence indepth tutorial:

1 First off, let's make a simple object, like this ellipse.

Note the square and round handles on the object, which indicates this is an .svg style object which you can modify according to the specific rules of said object.

2 This is of course no good, as OpenSCAD / dxf can't read this format. What we need to do is convert it to a path. [Shift+Ctrl+C]

3 Select the node tool [N], and notice how the handles on the object now look like gray squares. This indicates we now have a path.

4 Drag-select, or press [Ctrl+A] to select every node. With the nodes selected, notice how the handles changed again. The lines with spheres at the end tells us the segments between the nodes are curved. (Try fiddling with the points if you like).

This, again, is no good for the standard .dxf plugin in Inkscape, which only exports straight lines. (See point 8).

5 With every node selected, press the indicated button to "Make selected segment lines".

The lines with spheres on the handles are gone, so we now have only straight lines between the nodes. This would work, but doesn't look very smooth, does it? Undo your last action and continue to next point in the tutorial, where you learn to do it the right way. (Sorry about that).

6 With every node selected, initialize some mouseclicking action on the indicated button "Insert new nodes into selected segments".

This, well, inserts new nodes into selected segments, following the curve.

Press a few times if you want a smoother object, but don't overdo it now, you hear?

7 Feel free to once more click "Make selected segment lines".

This looks much better. The lines are straight, but due to the sheer numbers, they simulate a curve! Victory!

You can of course select only part of the nodes, if you only want part of the model smooth.

8 Now save the file as "test.dxf". You will need to select "Desktop Cutting Plotter (R13)" in the type drop down box.

Notice the help tells us we can only export certain elements. What we have done now is create only lowpolylines, which exports beautifully.

9 Start up OpenSCAD and use the following code to open up the file. (You need to put the .scad and .dxf file in the same directory).

linear_extrude(file = "test.dxf", height = 10, center = true);
There you go! Enjoy your Inkscape paths in OpenSCAD.

10 This works fine with any objects, advanced or not. Just remember to union the different paths.

Also note the part "Rap" is not just white text, it's a proper hole made with difference.

You can of course export several .dxf files and combine them in OpenSCAD if you need different height on some parts.

It can sometimes be difficult work with the .dxf file in OpenSCAD, as Inkscape exports the entire page, and it can be a bit tricky to locate where the object are. ~~I recommend you select everything, go to Document Properties [Shift+Ctrl+D] and "Fit page to selection".~~ Edit: See below. The problem is a bit difficult to explain, but you'll understand it once you have experienced it.

Take care not to overwrite your original .svg file if you want to be able to edit things later. It's much easier to work with objects than paths.

Edit 16.09.2011: I have found it easier to align the objects to point 0x0 (the bottom left corner of the page in Inkscape) and not center the object in OpenSCAD. Then you can easily stack several .dxf files in different heights.

Now go forth and make something awesome! Remember to share your .svg files on thingiverse, to go with the .scad files!

I hope this helped, and clarified some things. If you have further questions or suggestions, feel free to comment.

-Nudel

Mendel-parts.com - New v6 hot end and positive experience.

2011-04-11T06:44:00.000-07:00

I cringed when I read Camiels post at the mendel-parts.com blog the other day. It's easy to see the frustration, and he does have a valid point about the negative feedback getting the most attention. As I received a package from mendel-parts today, I'd like to share my positive experience with you, while I make a first-impression preview on their new v6 hot end design.

My order was in the €100+ range, which included a 5mm alu printbed and a few spares of the older simpler hotends (now discontinued?), because I know I can get that to work (at least for a day or two). I also ordered a bunch of bootlace ferrules, as I only seem to find insulated ones on ebay for some reason.

The most interesting item though, is this.

This is the newest v6 hot end design from mendel-parts.com, and it looks like it has great potensial. It's machined beautifully, and has a good deal of weight to it. The added weight might have an impact on a theoretical maximum speed, but my main goal is stability over speed anyway.

The only part I don't like is the thermistor attachment, as I don't trust kapton tape, and neither would I like to glue the thermistor permanently to the block. We'll see if I manage to build up the courage to tap a new hole and use a ring terminal with the thermistor on instead.

Another thing I'm a bit curious about is the gap inside the heater block, between the nozzle and the inlet. I have always understood the inside of the hot end needed to be a smooth as possible to decrease the pressure needed to push plastic through. This design have some pretty big threads where the plastic will pack up, and most of us have probably fought with hardened PLA. Yes, I understand they get the design to work very well, though I don't know if this gap has any down sides, especially regarding long time reliability and cleaning.

Edit: I have the peek block the wrong way around in these pictures. More info from araspitfire here.

Back to the order and lead time discussion.

I put in the order 3/26, got a manual order confirmation 3/31, and the package was shipped 4/6. According to the excellent UPS tracking system, it took less than 8 hours to ship the package the ~1000km from the Netherlands to Oslo. It then took 4 days to ship it the last ~100km from Oslo to me, let's blame the weekend for that. All in all I must say it was pretty good!

In total it took 16 days to receive my order, of which 5 days was in transit. I ordered on a Saturday, so the first working day was 28/3. Is 9 days of lead time something to make a fuzz about? I really don't see why people complain. I'd also like to add that they sent me a new printed baseplate for the v6 hotend for free, which they really weren't obliged to do. That's great service!

Some people will probably mention it, and I'd like to agree in advance; this wasn't a complete mendel kit, which may have a longer lead time. But for those of us who have a mendel in our possession, it's irrelevant, because we're mainly interested in fast dispatching of spare parts anyway. ~~And in that regard, I approve of mendel-parts.com, and recommend them as a webshop who delivers what they promise: high quality parts, and a decent lead time.~~

Update 01.09.2012: Mendel-parts has been getting a lot of bad press over a long period of time, and although the grief is mostly about Orcas, I can not recommend shopping with them until they fix their issues. For high quality extruder hot ends, check out J-heads at hotends.com and Arcol versions at arcol.hu.

Now I'm looking forward to trying out the slick v6 hot end! A proper review is coming up when I have some experience with it running, and made up my mind about it.

-Nudel

A coalition of obsessions.

2011-03-08T04:38:00.000-08:00

You like?

Small (35mm) fan for extruder cooling.

2011-01-13T03:53:00.000-08:00

I've been looking around for a small fan for my extruder, but most of the cost about $10 + shipping which I felt was a bit too high.

But dealextreme came to the rescue with a replacement fan for the Nintendo Wii. It only cost $3.60 including shipping, and I just received mine. It is not the most powerful thing, and I have yet to mount it, but I thought this might be of interest to others.

Dimensions are 35x35x15mm and it runs off 5v. The black lead is negative/ground, and the gray is positive. It comes with a small connector which you remove by lifting (hacking off) the tiny tabs. There are mounting brackets on the side, but they can easily be cut off if needed.

First blog, first post, first print!

2010-09-20T12:13:00.000-07:00

So, how do one start out one of these blog things? How about a historical event?

I hereby present Aida - my RepRap Mendel - and the first output she produced that did something else than not stick to the platform.

We have low stiction levels.

And it stayed put the whole time, oh joy!

RepSnapper even predicted the strings.

Hi to everyone on #reprap. Thanks a lot guys, wouldn't and couldn't have reached this RepRap milestone without you!

So, why am I starting up this blog thing anyway? I have a fever, and the only cure is MORE REPRAP. So I went to my doctor and told him, and he gave me a RepRap Prescription. How's that for a blog intro? *insert wacky smiley face*

A proper introduction to Aida is appropriate, and is in the works, meaning I have not even started writing it.

Have fun, all my fellow reprappers, and everyone else.

-Nudel