...yeah, well, as predicted, progress has been slower than I would have liked. BUT, we do have the various shafts for the machine sorted now!
Picture below is my own version of the "lathe" required to cut the shafts to length and to lay down the grooves for the retaining clips. Drill in a vice. Angle grinder with 1mm cutting disc. I tried the Dremel but the geometry was not quite conducive to accurate grooves.
Tip for anyone following - the grooves really don't need to be very deep at all. Shaft OD is 8mm. Retaining clip ID is 7.5mm. So the groove only needs to be 0.25mm deep.
I came close to going too deep on the fist shaft. We bought chromed shafts (not just straight mild steel) and leaned a bit too hard to break through the chrome the first time. Lesson learned - not probs after that.
Very useful thing was the old kitchen chair I used as a tool rest of sorts. Hard to be very accurate when going free hand.
Another problem with chrome shafts is that you can't mark the measurements on the steel very easily - had to wrap a piece of masking tape around the blanks so that I could set out the marks.
And - big news - we got washers in the mail (!!!) so we can finish most of the mechanical build. Still waiting for the threaded inserts though :(
We have all the electrical / power bits now too, so overall we're pretty much sorted for having all the pieces of the jigsaw sitting ready to go.
Raspberry Pi capability is rising. Been reading, taking notes, watching & mucking about.
So I figured I should publish an update on progress, but progress has been slow over the last couple of weeks:
Life has intruded and time has been a bit hard to come by
Still waiting for some critical bits from China - washers and threaded inserts specifically
Finished all the 3D printing - full set of parts done including a few spares
Most of the electrical / power items have been delivered already
Ran out of some screws, so had to order more ( I messed up the original order quantity)
And that's about it, right at the moment. The time thing has mostly impacted the Raspberry Pi control system part of the exercise. I have to read, understand and work through the documentation in a solid chunk of time, not piecemeal.
I need to extract the digit over the next little while or winter will be gone and the sun will tend to draw me outside the house. I need to finish the mods and put the dashboard on my car back together before the weather improves, too. More intent required.
I said "...by Christmas" when I started this project.
We're still still working through the prints (see pic below)...
Aluminium extrusions cut to length...
Most of the first round of orders from AliExpress have arrived...
Ordered a bunch more things related to powering the beast...
At some stage, I'll publish a detailed list of everything we purchase...
Revived an old laptop to run things through with a fresh Lubuntu install (replacing Win XP that replaced full Ubuntu that replaced Win Vista)...
The more I read, the more I'm getting a bit intimidated with the whole control system thing. I have zero problem with the mechanical & electrical build - I'll happy work away at that kind of thing all day, any day. Car-related tinkering is my forte. But the whole software part is well outside my comfort zone.
Early in my life I was into coding / software, but my interests subsequently drifted to mechanical engineering - with "computers" being essential tools but definitely something that specialists dealt with in detail, not me.
So with regards to all things "Pi", I'm rising from a low base. Going in I certainly expected a struggle, but jeez my brain hurts a bit at the moment.
I'm sure I'll work it out one way or another. Plenty of time. No hurry. She'll be right!
Sharing to perhaps save someone else some frustration...
Firstly, our Cocoon Create Touch (Wanhao Duplicator i3 Plus) has manual bed levelling, which is fine. A minor hassle, but no big deal.
We've found that using the preheating function on the machine well BEFORE we kick off with a print is a good move. Levelling the bed when it's at temperature is the go.
We've found it gives a more reliable start to the print. Previously, we've had random print fails on the first layer a few of times - extruder too close or too far away. I figure the aluminium build plate bends / twists a bit as it goes from ambient to operating temperature. We're only talking heat-related distortions of 0.1mm to affect things.
Preheating for bed levelling may be common knowledge, but I haven't read that tip anywhere.
Secondly, this morning we ran out of adjustment on one of the bed levelling nuts - something was amiss somewhere. A bit of investigating and we found that our x-axis gantry was out of level. We're not sure if it has been a gradual change or from a single event. Checking the gantry level was a part of the initial set up of the machine, but of zero interest since. It was a long way out of whack.
A quick check with a brickies string bubble level from the shed sorted it. We'll add that to the tool kit.
Our initial purchase of printer filament included a roll of black PLA, so we've started to print the wheels - design gratefully downloaded from those @Roger has shared with the world at his GitHub repository (https://github.com/Roger-random).
With the slicer set at 0.2mm layers, it's about a 15-hour print job - our longest to date.
Set it to go late afternoon, print overnight and it's finished before everyone leaves for work / school. Shut doors in the house to keep the noise contained. Our printer isn't too noisy, but it's definitely loud enough to have you stirring in the night wondering what that sound is.
No dramas with the first big print.
Yep. That'd be some stringing you can see in there. My son intends to fiddle with the print settings to see if we can reduce it, but it's not that bad. Easily cleaned up with your fingers.
#1: The 0.2mm layer height we chose is more than adequate. Could probably get away with 0.35mm.
#2: When I held it in my hand, the wheel was bigger than I thought it would be. I'd obviously seen the STL model and its nominal dimensions, but I still found it strikingly large.
#3: There is more to the wheel design than I picked up from looking at it on a screen. Again, once you have it in your hand and push / poke / squeeze / twist, the detail pops makes sense. Built-in suspension, both perpendicular to the axle & around the axle! With the wheel being a single piece of plastic, there is obviously more springing than damping going on, but it's pretty impressive. Noice!
@Roger 's budget for the original Sawppy was US$500. That's about AU$750 right at
that I'm going to be paying a lot of postage, if we get in
under AU$1000 I think that will be OK.
The need for postage comes from living on the western edge of Australia -
a long way from anywhere.
a reasonably determined effort to try to get the parts required from local (Western Australian) suppliers, but I gave up the fight before too long. Another long
story short: Too costly. Too limited. Just too hard.
online ordering from Australian businesses on the east coast yielded roughly the same
story. Ebay same. Amazon same.
Hello, AliExpress! Everything you could possibly want, you just have
to wait for it to arrive.
#1: Aluminium extrusions - Just couldn't get the right profile
let alone the right dimensions in WA. About $4 per metre length from
AliExpress (I got black anodised). AU$30 delivery for 5 x one
metre lengths. Took just a week to get here.
#2: The servo motors. I'm sticking with Roger's recommendation on
these because I don't know enough to argue. Found the right ones on
Amazon US - AU$22 or something, plus shipping. BUT you can't buy
third party items from Amazon US and ship to Oz. Got referred to Amazon
Australia - same servo motors are now AU$25 plus shipping. And they only
have four (I need ten). AliExpress? Some RC shop has a thousand on
the shelf. AU$22 including shipping and you get a free debug board.
I sat down one night a couple of weeks back and ordered about
AU$400 worth of parts on AliExpress. It's starting to arrive now :)
It drove me a bit nuts trying to choose an a 3D printer for our planned Sawppy adventure. Several weekend nights spent researching seemed to get me only marginally closer to actually picking a machine. I nearly pulled the trigger on a few occasions, but always found a reason to pause.
I wanted to buy the machine locally rather than from a random overseas supplier - trading dollars for some certainty. A local warranty and local support seemed important given I knew slightly north of nothing about these things aside from what I'd read on the interwebs.
Long story short: I stumbled upon a local company (well, Melbourne-based - 2500km away) selling a badge-engineered version of the Wanhao i3 Duplicator Plus. The "Cocoon Create Touch" is the machine. AU$500 at Aldi. AU$400 for a refurbished unit. Plenty of reviews on YouTube, if you're interested.
We've had it for about a month. Minor issues. A few foibles. Nothing bad worth mentioning, to be honest.
Good things to mention are that it's proven reliable and more than able to print the miscellaneous thingiverse gadgets we tested it on.
In terms of price / capability, I think I found a machine good enough for the job.