3D Delta Printer D16_EBOT part 1

Hi,
As from 2014 I started to develop and build my own 3D Delta printer. At this moment my little guy is doing exactly where he was build for, printing nice objects and it let me test all kind of new things I like to develop.
I named the printer D16_Ebot. see attachment as a picture and also the 3D pdf file. (Double click in the picture and you will be enabled to lookup the printer from all directions as well as with the help of the parts list tree, hiding and un-hiding parts and sub assy's.)

A video with the D16_Ebot in action: see Video D16_EBOT

The D16_Ebot has a heated bed of 230 mm whereof 200 mm in use; the print height is 230 mm but is in fact only limited by the length of the used poles.
In the video I do show an inductive heated bed what is still under development and not part of the Delta printer design project.
For the electronics I have used a BeagleBone Black rev.C and a controller board BeBoPr++
Because I was used to the software LinuxCNC that is around for many years including a huge user group, I did used also this time LinuxCNC (Machinekit)
If I build again a printer, and I will, I will use a smoothieboard.

The maximum speed tested for still decent prints is 80mm/sec for 1.75mm filament. More tests will follow.

The poles are "Silver-steel D=16mm"
The base and the top is 18mm MDF
The effector and vertical slider blocks are Nylon
The 6 aluminum parallel arms have a diameter of 12 and are 296 long center to center with 10mm balls
A pull spring keeps all together in the D=10mm joints like your own elbows are hold together; 100% backlash free.
Magnets will do the job too but at a crash with your hot end, all arms will fly around. A magnet will loose all forces after 1 mm detach, a pull spring does increase his force, trying to keep all in place, again like your own elbow.
The heated bed on 3 Points and a tempered glass plate or an aluminum Alcoa casted plate. A aluminum cold rolled plate doesn't work, .. no that's the problem, ... it works all the time.
If you keep yourself strict to the theory of how to positioning a plane and respect elongation factors for aluminum in you design, an aluminum plate is the way to go. There is no need for an auto leveling system at all. That honors also my advice, "do things right the first time"; it eliminates a fix like a leveling system.

Talk to you later where I will go in detail and will post all basic drawings and parts list.
Have a good one

Edited 1 time(s). Last edit at 02/29/2016 11:05AM by evandene.

So I figured out that not all free picture upload/share websites are for free but "postimage.org" should work, so now I can show you my D16_Ebot printer in this blog.
But I see I do need to work on the quality. (Some tips could bring me up to speed here)

I will describe the build here and for those who do need the step files, please let me know.

The base is a sandwich of two 18mm MDF plates. The MDF material available in Belgium has a very poor quality and low pressure.
When machining it keeps on showing the fibers on sharp edges no matter how sharp your tools are. Also the binding material used is causing your tools wearing out very quickly. So keep an eye on the quality of your MDF.
This sandwich construction gives a solid stable base for the printer suitable for hiding the motors and electronics in a safe place. And yes, I admit that it is not the cheapest way but with my experiences of 40 years building machines is that stability and quality in your base pays off at the end 100 times.
At the top a third same shaped plate with the same hole pattern is used to make a closed loop of the design. The silver-steel pools used are perfectly aligned by the CNC machined holes in all the plates. This assures no alignment effort needed and later the movement of the parallel arms will be as the algorithm expect it is and that creates the highest precision possible for a Delta printer. Doing things the first time right pays off all the time.
The vertical covers, mounted against the sandwiched base do carry an ATX 300 watt power supply with the fan nicely outside, at the front a 7" touch screen, and at the right side an extra 12 volt fan for extra cooling of the electronics. The front plate with the 7" touch screen can be removed and ALL electronics including connection do move out too.

My first post has a 3D pdf attachment were you can manipulate the assembly by double clicking in the picture and using the part tree switching on and of parts and sub assy's in order for you to examine the design.
Have fun and talk to you later at my next post.

Edited 1 time(s). Last edit at 02/29/2016 11:04AM by evandene.

When starting a new design it's good to describe as precise as possible what you want to achieve. While doing so the design iteration process does start automatically and although you're on your own in your study room or so, you start already a kind of design FMEA.
When you're ready with the design specifications you start your design in your favorite CAD System. My system at home is Alibre, it's named now Geomagic Design. But of course any CAD system will do the job. Sometimes I use also Autodesk 360 or Googles SkechUp.
Please find attached my Design Specifications made before I started the real design. Later on in my postings you will notice that some of the specifics are not or not yet realized because of priority settings but the ideas are still intact.

Talk to you later at my next posting

Edited 1 time(s). Last edit at 02/29/2016 11:05AM by evandene.

Using a "reel unwind-stand" for the filament coil or reel to unwind is a great added value to your 3D printer and I will explain you why.
A full filament reel or coil has a weight of at least 1 Kg. Most of the reels are just hanging in the core while the extruder is pulling on the filament, unwinding the filament and at the same time pushing the filament trough the hot-end, that's quite something.
When I count with a friction-factor 0.2 and that gives a friction of 0.2x1.000 gram=200grams or 0.2 Kg.
To feed filament into the extruder I need accelerations up to 15M/s2. That makes a pulling force of 3 Newton that comes on top of the pushing force needed to get the filament extruded. The pulling force translated into the extra torque for the extruder wheel = 5Ncm.
With a proper designed stand alone unwind stand you can eliminate this extra torque completely.
What you need is a little DC motor with gearbox (Robotics) a power adapter and a micro switch. When the filament pushes the lever up, the micro switch gets trigger and the motor unwinds the reel a little etc, etc.
Of course most parts are 3D printed, "what else"?
See my design for a filament reel unwind stand.


Edited 1 time(s). Last edit at 02/29/2016 11:02AM by evandene.

I started my build with milling basically three the same plates. Two bottom plates who are sandwiched with spacers, holding the electronics and stepper motors in between. and a top plate.
The three plates have all the same hole pattern for the D=16.00 mm (0.63") silver steel poles. This makes that the hole pattern is super precise and should enable me assembling the parallel arm bearing blocks without alignment deviations.

The simplicity of a delta printer is obvious.

See attachments
The bearing blocks have integrated belt clamp functionality.


Edited 2 time(s). Last edit at 03/06/2016 04:09AM by evandene.