stevedee wrote: ↑Sunday 19th December 2021 10:24am
Wow! Brilliant work Mike!
I do hope you find the time to complete this project, and maybe compare its performance with your Creality Ender.
But I know how difficult it is to find time for long term projects, with so may other demands on your time.
Thanks. A lot of hours have gone into it so far. The frame and all the plates are made with Stainless Steel. Except for the floating portion of the bed. That's aluminium. The stainless didn't do me any favours as it can be a bugger to work with. But it also welds so nicely.
I have to confess that I have not used my printer since mid-October, and even then I was just demonstrating it to a mate that came over one evening. I haven't been able to find anything I wanted to print during the last couple of months.
Yeah I wonder where I will be with it in another 6 months. Hopefully still at it. Right now I've got a couple of projects I'd like to try for my DSL and for my telescope. I found this
Bokeh Mask on Thingiverse and gave it a print. Its a cool effect but would like to remix the design to work better (falls off too easily and the masks drop out if you move the camera). I'd also want to mount a camera to my telescope. It'll make it easier to show the kids the planets if we can do camping this summer.
I thought Creative made sound cards!
I know right!
Those little micro-switches seem to do the job, its just that I would have thought the repeatability and hysteresis would have affected Z-zero, the very thing that needs to be spot-on. Also, I should imagine opto-source/sensor arrangements come with their own set of issues due to light-scatter, and maybe variations in sensitivity. Another consideration is how to ensure that if the motor drives through the detection point, the motor doesn't then get switched back on and damage something. At least with a micro-switch, once its operated, it stays operated. I also assume that they are wired in a relatively fail-safe manner, i.e. switch "open" stops the motor rather than "closed".
Well technically the way Creative mounted these limit switches are wrong. You never want your flag to come down onto your switch. It should move across it. This way if the switch is not set properly, or say a motor/actuator is wired backwards, or the response time of your actuator is slow, you never crush your switch. But this orientation they are using will give them better response from these type of switches.
[/quote]Your frame is a work of art (
even the cat thinks so!). What is at the heart of your controller (.
..Arduino maybe?).[/quote]I enjoyed working on that frame. I cut and coped all the tubes by hand in the mill. I had to make an aluminium insert to stabilize them as I did this. Otherwise the sides would just bend and be a mess. I was really pleased how they turned out. The plates were all cut on a CNC mill. I just took all my CAD drawings and imported them into BobCAD (think Cura for machinist
). I used our TIG welder to weld the frame. I had a horrible time with the tubes. They are SO THIN!
I originally was going to to complete welds all around each joint. But I was having so much trouble I just stitched welded them in stead. Now that I have a few more years of practice on that welder, I wonder if I can do a better job or not. I think its best to leave sleeping dogs lie.
The controller is a ATMEGA 128 (I think) which if memory serves me is what's used on the Arduino Mega. Its just this chip does not have the Arduino boot loader installed on it. This Arduino program allows users to store programs on the chip without needing to play with the chip's 'fuses'. Thus the Arduino code makes it more convenient for the average person to program these chips at the expense of some lost memory. And Merlin doesn't rely on the Arduino code so its not there. But otherwise its the same chip and has a lot of similarities to the design of the Arduino Uno/Mega boards.
Our Creative boards don't use ATMEGA based boards. The ATMEGA are slower. So I will be limited in the half stepping I due for the steppers. Essentially these stepper motors take 200 pulses to rotate one full turn. But using half/quarter/etc stepping technique, you can increase that by 2x, 4x, 8x, etc. This produces smaller motion per pulse and also reduces the motor's noise levels.
I'm really not sure about using wing-nuts for adjusting the bed, but I guess you are limited on space. The adjusters on my printer are at least 2" in diameter, and I still need a very gentle touch to make fine adjustments. I can't remember very much about screw threads from my days as an apprentice (...seem to remember UNF were the finest pitch) but I guess the finer the better.
Yes after working with my Ender, I think this will be an area that will need improvement.