Rostock 0.15mm layer height

Had a go at a model using .15mm layer height. This is a 50% scale of the original model. The original model would have taken about 8 hours to print so I scaled it down quite a bit. This took just over 2 hours. I would like to try the full size one as there would be alot more detail.
Pretty happy with the quality.. might have to give .1mm a go next

Minor mods to Rostock

Hi All,
Just thought I would post some minor updates that I made to my original Rostock.

Pulley Case Covers: I found that anytime I put anything down on the desk it would seem to be attracted to the moving pulleys and belts at the base of the rostock while I was in the middle of a print job hehe.  So I made up some simple covers for the motor mount at the bottom of each axis.
The stl can be found on thingiverse: http://www.thingiverse.com/thing:53556

Kossel Effector: I decided to replace the original rostock effector with the newer simpler design from the Kossel. This image shows the original design sitting on the print bed with the new, more simple one from the Kossel already fitted floating just above.
The new effector design is lighter, allows a more unobstructed view print job in progress and allows the effector rods to be attached in a more simple and secure fashion.
If you do use this part for the standard rostock you must make sure that the spacing between the effector rods at this effector end is exactly the same as it is where they on the X,Y and Z axis. The scad file from the kossel will allow you to adjust that dimension if necessary. I just used the standard spacing as the spacers from my Heim joints allows it to fit perfectly.

 

 

 

Herringbone Gears: Finally, just because I was board, I replaced the standard gears on my extruder with herringbone gears. These have less play and seem to be a bit quieter.
I just used the standard parametric herringbone gear openscad file that you can find on thingiverse adjusting the gear ratios for the ones I use on my wades on this Rostock.

 

 

 

 

 

 

 

 

 

 



Rostock printing real things :-)

Today I actually designed and printed something other than a trinket or a part for a printer. I wanted a better way to adjust the vertical angle of my home theatre projector. The commercial mount has the projector mounting bracket hanging and pivoting from the one point. Unfortunately this poses a problem as the strange mount on my projector means it is slightly back heavy. To add to this I have it mounted on an articulated arm so I can fold it back to the wall when not in use and then swing it out to optimal position when i use.
To make alignment to the screen easier, I used the free creo elements cad package to design an adjustable bracket and then printed out the parts. The images below show the results. It works a treat.
It adds stability to the projector as it is not mounted from two points on the bar and can quickly be adjusted if necessary by turning a thumb wheel to raise or lower it.

This is the design in the Creo Elements cad package.

 

This is the end result looking from the back of the projector. The bottom nut is a nylock nut that holds the threaded rod and in the top clamp section there is a standard nut in the thumb wheel adjuster with some washers top and bottom.

 

Rostock more fine tuning 0.15mm layer height

Another big day today.

•  I added the LCD controller to my Ramps board - as well as being able to monitor or control the printer, I particularly like how this can be used to slow down or speed up the print job as required.
• Added mmall LED posts to the front axis to light up the print area - These are attached to the lower part of the Front two smoothrods. The carriages never come down that low and they generate nice highlights so you can keep an eye on the print job. 
• Switched to KisSlicer for slicing the stl files - This seems to make much nicer prints, it is much better at handling shallow curves and seems to generate much more logical pathing. its also allows you to print the outer most perimeter slowly and then all the other very fast.
   
• Started printing at 0.15mm layer height  - and this really starts to allow details to show in the models. Really happy with these results. The .4mm layer height I used to print at seems so far removed from what I am getting now. It is still not perfect as I am still learning how to tweak KisSlicer.

The image on the left shows the new LCD controller and the print area lighting. The other shows the owl from the other day (printed at 0.2mm) and now the the ape and the funny looking gargoyle at 0.15mm.

Fine Tuning the Rostock ...Success!!

I spent this long weekend resolving some issues on the Rostock.
Two issues that were causing intermittent problems were:

1. The Teflon tube on the bowden occassionally working its way loose during a print.  
   This was a pain. If I tightened the clamp up too tight it would crimp the tube and restrict the path of the plastic filament. I tried a few things like filing the outside of the tube to provide more grip, adding some tape, etc.
   Finally I had a eureka moment when I suddenly woke up at 3am Saturday moning. I Then couldnt sleep, so I got up to try and implement the idea. I added a threaded nut onto the Teflon tube and redid the connection so the night is locked inside and cannot pull out. Success
     
2. The extruder sometimes skipped when feeding filament during parts of the print that involved laying alot of plastic quickly. Basically did not have enough torque. I redesigned the gears shrinking the drive gear a little and increasing the size of the secondary gear to increase torque. 

Basically this resulted in the quality of my prints going from this:

 

To this..



 

This last print was at .2mm layer height abd too about 4 hours. I had to vary the speed at certain points to allow the filament to dry on the smaller diameter parts

 

Rostock 3D Printing Vases

Well I printed one of my longest jobs on the rostock. A couple of vases. All up they took about 5 hours or so.
I have printed them in plain white as they are translucent and I intend to put some of those LED flickering tealights in them.
The one on the right is after doing more tweaks to the unit. I added sides and crossbeams to increase the rigidity of the unit which has decreased vibration during printing substantially.

 

 

Rostock Finally working Accurately- YAY!

Well I have been slack of late and never got around to debugging the Rostock printer.
I have had a long outstanding issue where prints were not perfect dimensions in X and Y
If for example I printed a large square 200mm x 200mm it would not be perfectly square. It would be out by a couple of mm in 1 corner.
I tried all sorts of measurements but could not work out the issue.
As I had a few days off over new years weekend, I decided to bite the bullet and fully rebuild it.

I totally dismantled it and cut new base and top boards. Assembled and squared everything up making sure everything was square and all rods are exactly the same length from the print centre, both Top and Bottom.
As mentioned in a previous post, I also replaced the printed rods and joints with manufactured Heim joints.
This time it all works very accurately.
Things that helped that I did not have as an early adopter for the first build:

• A good set of precise dimensions for the base and top boards. Previously its was all angles and distance from centre etc. Very difficult to get perfectly accurate. This set of dimensions lets you locate all the key points just by measuring from the top left of a rectangle board.  http://www.thingiverse.com/thing:34359 .  I still calculated the build centre point which is 175 In from the left and 175 in from the back. Lines going out from the centre point at 120 degree angles intersect the midpoints between each of the whole pairs.
  An important note about the diagram is that the holes on that are marked as 8mm. This is wrong they are only 3 or 4mm and are used to secure the plastic parts that hold the rods. The rods do not go through the board they are on the outside edges of the board.
• A good calibration guide: http://minow.blogspot.com.au/  This is an excellent source of information that clears up so much of the black magic. Thanks minow :-)
• A second try :-)  My experience from the first build made the rebuild easy. Basically it was done in a day.  

This time around I did not add the threaded rods for support. I am going to add some sides on the left and right sides that extend a couple of inches beyond the the back of the unit. I will then add a threaded rod X across the back for stability.

I will post an image once I have completed the build.

Replace Universal Joints and Rods

Well it was time to make another mod to the Rostock 3D Printer.
I purchased some preassembled effector rods with Heim joints to replace the rods and joints I printed originally.
These rods are steel M3 rods with Heim joints (a kind of ball joint) fitted to the ends.

Heim joints are a loop at the end that rotate around a ball.
I have included a video

I still seem to have the printing issue though which basically slightly distorts the object as you move towards the front right corner in x/y.  Its only slight and you dont notice it on most smaller objects, but it is really annoying me. If I print a 150mm square. It is not truly square. It is slightly smaller in the front right corner by about 1.5mm.  Its like that corner is pushed in towards the centre slightly.
It must be caused by the position of the 3 axis as replacing all of the rods did not change the problem. Next step I will make a new base and top to ensure that all 3 axis are perfectly positioned and square.

Rostock 3D with improved extruder

I made yet another change the the Rostock. I have been using a wades extruder but the high ratio between the gears had been causing some issues. Although it had a lot of torque, it is a bit slow to respond to the big retracts needed for retractions through the bowden tube. Because it need such long retractions and such a hi ratio, retractions would take over 1 second causing pauses as the head waited for the retract.
So I created a new set of gears that have a much closer ratio (almost 1:1).
The response is much much fast now and it has improved print quality too.
here is a little video. Nothing too special but its printing a complicated print and the extrudes start and stop exactly where required even the little drops:

The camera really seems to be sensitive to the noises from the printer. this video makes it sound like its making a racket but its actually nowhere near as harsh as it sounds here.

 

New Rostock Firmware installed and working

No new images today but I just wanted to report that the Rostock is working well with the new firmware.
I did initially have a teething problem where my extruder was not working after the upgrade.. but I found the magic setting I needed to adjust. Interestingly the parameter was set the same in both versions of the firmware :Default Retract Acceleration. Its possible that it may not have been properly implemented in the first version of the firmware. I am not sure why the value had to be different but it is working again.

One of the biggest changes in the firmware (amongst many) is the removal of the bottom end stops. These are no longer required for leveling the effector or finding the home position. Although this means the Rostock no longer does its little dance when you home all axis, it simplifies the how process and is more straight forward. This also means you may be able to use other controller boards that do not support both min and max end stops (like the Gen6 for example). Although I have not tried any of these.

I am still working on getting the best out of the bowden extruder. It still occassionally fails to deposit small amounts after a retract, but it is getting better with each tuning.

Also I manages to print several complex objects using Pronterface.exe. The issues where this used to cause pauses during prints seems to no longer occur.  I printed from pronterface for about 3 hours straight without a hitch.

The print quality of the layers is really good to my eye, except for the occassional miss with the extruder. If I can nail these issues, it will be almost flawless.
   

 

Another Improve in Rostock print quality

I think i have solved the lumpiness issue now. I was correct in that I think it was being caused by a big difference in speed between standard perimeters and Small perimeters. This would result in little blobs as it slow down and the extra flow of the bowden would deposit a bit too much plastic. I changed the slice settings so they both print at the same speed (90mm/s) and this seems to have eliminated the "warts" I was getting on the outside of the objects (See Yoda below).
I had to post process this picture to remove some of the colour. The camera was having a hard time with transparent red again.  This is Spoctopuss a .2mm layer height.

 

A Yoda I have printed hmmm?

Well After many failed attempts to complete the print job of Yoda. I finally succeeded.
With previous attempts one axis would miss a step somewhere along the way throwing the whole print out. On rostock it is hard to tell which one was the culprit so I went back to basics and checked the reference voltages on the stepsticks and found one was lower than the other two. I set them all the same and managed to complete the whole print at .2mm layer height with a .5mm hot end.
Its a long way from perfect but at least it printed.
The image on the left shows him with the support structures still in place.
The main issue that will affect all prints are the small blobs... it is extruding inconsistently. Its possible that with the bowden extruder it is having trouble if I have too much of a speed differential between the speed of the small perimeters and large perimeters. Flow control could be an issue there. I will try to make the speeds more consistent and see if that helps.

The holes in the ears I think are cause by them simply being too thin in the model so I am not too worried about that.