DIY Aluminium 3D-Printer, build 2 (page 4) (Page 6 of 7)

Thanks!
Yep, it had same jerk settings! I even checked microstepping jumper settings, but they were also same..

Could it be pronterface which I'm using?

I checked those with winmerge and didn't find any differences, but yes I can post it here! Help is always welcome

As you can see from the teaser, I made new extruder for this printer. Some may remember earlier design with double pinch wheels. I decided to leave them and go with traditional spring loaded wheel. This have watercooling still There is flexible driveshaft which turns 1:25 worm gear set. Filament is 1.75mm and can't go to 3mm without modifying pulleys. They are stainless steel and hobbed with M3 tap so I believe it's too small for 3mm filament.
I did measurements with fishing scale, and I'm pretty satisfied. It handled pulling force of 25.2kg and filament pulleys didn't even slip. I stopped testing because bearings for worm started to move because they are only glued to their place. Sadly I didn't have time to take photo of scale, so you have just to believe me
I have done few prints already and the thing works pretty well! Haven't really made any tuning yet but it works well. Watercooling leaks a bit, so I need to fix that. Test piece is printed from bottom to halfway with 100mm/s (5000mm/s2) and above that is 250mm/s (11000mm/s2). Ugly ripples in corners, but that was just to test if machine can handle those speeds Anyway, here is photos. I'll add videos later when I get good material!

https://dl.dropboxusercontent.com/u/526 … 552810.jpg

I added configuration.h files in attachment If Timp610 could watch them!

Edit: And the whole thing weights 160 gramm!

Better watch out or you might end up in business making these

Yea, I need to be careful! And thanks

toobyaas, Nice video!  what are you using for a heat bed?  DC PCB; AC Silicone pad?

Hello! I have something small to tell this time

I designed (fourth design..) a fan holder which blows air to nozzle. This helps a lot when printing small parts. Though I'm using pretty much only ABS, I need to use fan!

And when I got it ready and working I started tuning my extruder settings. Mainly retraction. Before this tuning, hotend did always leave a small blob in the start of every move. I tried pretty much everything, and came up with conclusion that blob is caused by drive shaft being springy (of course since it is a spring). So then I got an idea. I added hysteresis fix to my firmware so I wondered if it works with negative digit. And it did! With -0.09mm fix and 1mm retraction I got results what you can see in pictures. On the right is first try and middle is last. I would say that is an improvement!
So on every direction change it moves filament 0.09mm less than gcode says. I'll tune that still, but I thought that maybe I should share this with you.
I'm planning to buy new steppers to every axis, because these are pretty weak. For example, it can retract only 11mm/s.

Hello! Long time from last post..

I've been suffering with lack of motivation with this thing, so I there is no progress in part manufacturing. Though in last couple weeks I found my motivation and pretty much designed the modifications!

Here is changes:
-Linear rails from 12mm chromed rod
-Linear bearings from brass or bronze
-CoreXY belt system (GT2)
-Aluminum bearing holders/X-ends/everything
-Direct drive extruder
-New watercooled hotend

I desided to go with CoreXY since there is lots of work to do anyway, so it doesn't matter. There is so much more pros with it, comparing to H-belt assembly. Carriage twisting haven't been problem with my H-bot design, but I wan't still change to CoreXY for increased stability. It will have also shorter belts, so there might be less stretching and more accuracy. Only negative thing is that it might be difficult to set exactly same tension for each belt, but I don't worry about it!
As you can see from my great drawing, it isn't ordinary CoreXY path. I'm doing it in two levels like Fabtotum(http://blog.fabtotum.com/blog/2014/04/0 … -to-share/). And motor location isn't in  stationary 180 degree turn of belt as usual. Belts are going from behind and they are not crossing. I think it's great thing! In demo drawing you only see one belt but it's not different from another, only going 10mm lower. With this kind setup I can keep the same style belt tensioning blocks with very easy access in front of printer.

Negative thing in these modifications are that moving mass is doubled comparing to existing design. CAD software says it's about 1.4kg + bolts, extruder etc. I'd say that is acceptable for (hopefully) increased stability and accuracy.
I'm making direct drive extruder because it's easy and reliable solution for first. I don't want to play with tons of problem at the same time. So when printer itself is running well, I start to develop different kind of extruders(Nema 8 stepper is waiting..)

If I'm lucky, part manufacturing starts in next week! If someone sees any problems with my CoreXY design let me hear that! I thought that the angled path you are seeing in demonstration doesn't matter since it's in fixed place? It's rough demo, so if I'd go with that those pulleys would crash. In real desing there is more room

You can also suggest some good stepper motors! I'm looking for powerful and fast enough motors. Maybe 60mm long versions?

Thank you!

Only negative thing is that they are shipping from china, so I need to pay import duties if order costs over 22 euros. But they are still pretty cheap.

What do you think about this motor? http://www.omc-stepperonline.com/nema-1 … -p-21.html
There is 2.1A and 1.2A version of that motor. With 2.1A my stepper drivers will probably be very hot, but is there any benefits why I should choose 2.1A motor over 1.2A? 2.1A motor does have lower inductance. Does it matter?

Some progress:

I haven't ordered steppers, since from omc-stepperonline postage would be insane. I'll just order wantai 4.4kg/cm steppers which I can get reasonably from ebay. I have now these so there will be great improvement anyway http://www.ebay.com/itm/251592343083?tf … lgo=origal

I wanted to design small and rather lightweight extruder. I decided to go with 3.15:1 gearing(which was sourced from highly geared DC-motor of oil separator) and very short nema 17 stepper motor(http://www.ebay.com/itm/331394458350). I also made watercooled hotend for it since my previous design was also that kind and it worked well. Designing of nozzle and heatbreak is similar to E3D V6.

This whole package weights just under 300 gramms which are about same as normal sized stepper motor. Altough weight isn't so important thing in my printer because there is no printed parts in strucutre, so moving mass is higher than usual in any case. But many little weight savings makes a big difference in the end!
I have printed couple test prints and it seems promising. It can easily achieve 30mm/s retractions and print over 150mm/s!

I bought also smoothieboard for it! And as usual, here is video:

Did you have to add headers for the display connection? I'm going to be adding headers so I can sync a couple of stepper drivers together for my 2 z-axis screws, perhaps I should add any headers I might need to attach a display some day if I decide I want to do that.