Quote Originally Posted by richardphat View Post
Oohh ,if you talk about the resolution, again, should you be worrying that much? I don't think so, because you're likely going to use NEMA 17 stepper motors(1.8deg) and you can do microsteps. Even that, depending on if you use belt or string then it may or may not matters. But keep in mind that your nozzle will likely cripple all movement and you will have srhinking that outcomes when speaking of error/tolerance.

When I was mentionning overconstrained, I did not mean on a 3D cad perspective, but what you mentionned about the number of rods for each carriage. Because having myself with 2 Delta self assembled, I see flaw where the hot-end mechanism wobble.

I designed my laser burner printer based on 3/8th rod I found from inkjet printers, the linear bearing cost for this typical dimension cost way too much and I have to scrap the whole design. I decided to downgrade to 8mm shaft and use LM8UU bearing.
The cost for the linear bearing drop from 15 to 2-3$/unit.
Microstepping imo is not a reliable method of positioning. Yes it works to a degree but the greatest precision comes from using the steps of the motor directly. I will be using 17's which gives me 200 steps per revolution. Couples with .1 pitch lead screws gives me 2000 steps per inch or a potential vertical resolution of .0005" without microstepping. I don't care to do the math to figure out how the vertical resolution relates to horizontal at the moment, it's been a rough day and I'm a little burnt. I realize that I will have material shrinkage in my prints but that can be compensated for fairly easily IF the machine is built properly and can print repeatably. For instance, a 1% shrink which is typical for ABS means all I have to do is scale my parts to 101%. I don't need half thou accuracy in my prints but I use my printer(s) for prototyping purposes first and trinkets second so accuracy is important to me.
As far as the linear motion itself, acme screws with doubled nuts as I mentioned, industrial rods and bearings, and so on. It's not going to be a cheap build by any stretch of the imagination. I'm guessing somewhere in the area of 1k US by the time I'm done just to buy the parts I need (not including printed parts that I will make on my existing machine). So on par or above the cost of many fully assembled machines but with vastly superior components. Maybe that will translate into a better printer, maybe not. Time will tell I guess.

Quote Originally Posted by JohnA136 View Post
I like your design so far. We built a couple of Kossel Deltas, we printed all of our own plastic parts and sourced out the hardware to various vendors. Both have heated build platforms and both print very well. We have pony printed PLA on these machines because they are open framed and we already have six different closed frame printers for ABS.

Of course, the downside on the Kossel is the Power Supplies do not fit under the machine. We also have our Ramps Boards mounted on the outside of the frames so we can have active cooling although I have seen some Deltas with the boards mounted under the Build Platform
Part of my design criteria is to fit the power supply under the machine. It means a taller base and a taller machine but a cleaner finished product and one that is easier to situate on a desk and/or transport. The board I haven't decided on a mounting solution for yet. It may live under the machine as well with a fan ducted to outside the frame but I'm still working on the basic mechanical design so I haven't gotten to the electronics yet. The frame is being designed with the intent of closing it off so I can print with whatever I want. I haven't decided on hinged or fully removable panels yet though.