Nice. And welcome back.
The polyurethane casts look nice. What did you use, EasyFlo casting resin?
Nice clean mold too. Silicone based?
Look forward to seeing more…
very cool look forward to see is roll/walk what gear ratio did you use for the motors?
kind regards
Thanks. The resin is IE-3075 from Innovative polymers, more viscous than water but has great mechanical properties. And yup, the mold was made of QM262 from quantum silicones.
Thanks, Codemaster. I really hope to have my bot as complete as yours soon. It looks awesome.
I used the 10:1 HP motors. I was aiming to get a little speed out of them. Not a very high ratio but I should still be able to get around 32 oz of force pushing the bot.
Cool I chose 100:1 its alittie slow but very powerful I was scared of it not moving more than the speed of it
How did and for what did you make the molds from are they heat resistant or not?
I will be working on my code in the coming week or two just shout if you what a test program or two.
I see your leg has a foot instead of just track, how do you plan to get from the stand to ride positions and back with that foot in the way? I found it very difficult but in sure you have got a plan.
Kind regards,
Codemaster
P.S. Awesome as always
I made the molds by machining a mold positive into prototyping board then pouring in silicone to make the negative that I could cast parts in. The silicone I used would be ok up to 200C but I don’t think the resin gets higher than 30 or 35C while curing.
I think I could just do a sort of lift and tuck movement with the leg and it’ll be alright; not quite there yet. And thanks, I’ll give you a shout if I need a program. Are you using a propeller?
Hello,
I am using the propeller with the ps2 controller and the same motor controllers as you.
I’m trying to to make my programs easier to convert from I robot to another and improving the servo offsets.
But I need stronger servos before I can continue making my walking sequences.
Kind Regards,
Codemaster
More progress.
I’ve nearly finished the legs. I’m still waiting for the the stock to cut the other axles and some photointerputers to use as enoders.
Here’s an ‘exploded’ view of the main parts for the leg.
Another pic of parts for the legs… and my ironing board.
And the pic of the four legs; 3 sans tracks.
I’ve just got a few more parts to recast then I can move on to the body. I’m gaining excitement again and regret falling away from this project for so long. It’s been so long that I have to reverse engineer the board that I designed, but that shouldn’t take long. I hope to have another update soon.
looking good
cant wait to see it walk :mrgreen:
Awesome work… really… 
That make me want to try moulding
I’ve made some progress. I machined a couple molds for the body. Still need to do 2 more. I’d like to pour the silicone but the molds are too big for my vacuum chamber and I don’t want to risk wasting the material. It will be worth the investment to get a bigger one.
Quick pic.
I’ve also been working on my algorithms for foot path production. Here’s an excel screenshot of the algorithm I made to generate footpaths for turning. The box in the middle is the quad, each leg at the corner. The large blue dot is the center of rotation. The big axes is the global coordinate system, the small sets of axes are the local coordinate systems for each foot. In this spreadsheet I can change the step length and steering input and it gives me a good visualization of where the bot is allowed to step.
Here’s the file if you want to play around, try changing the turn input to numbers between -500 and 500.
QUAD GAIT ALGORITHM TESTS.xls (113 KB)
Wow… that mold is awesome.
Made on your CNC … it look so smooth…
very cool when you gonna get walking its an agonising wait to see it in action :mrgreen:
Thanks Guys 
As for walking, hopefully by the end of the year? 
I am hoping to have the body done and the robot 90% assembled within about two weeks. I could at least make it stand for you 
What are you using to make the mold… pictures of the process…???
The material I cut it from is Prolab 65. It’s a medium density prototyping board, like a dense foam with similar weight to MDF but holds detail much better.
I’ll try to get some pics of the process up tonight when I get home.
So, DialFonzo, this may not be exactly what you’re looking for, but it’s from the beginning.
First, a tour of my spacious 14 sq. ft. shop.
Yeah, that’s it.
Step 1: Design
I’m going to follow the production of the highlighted part.
Step 2: Create a mold cavity with a 5-6mm margin from the part. I cut it close in this case due to space constrictions.
For each case I will make the mold walls at least 3mm taller than the part. As long as you cast on a flat surface then this margin isn’t extremely important.
Step 3: Mate the parts, set origin according to the CAM program you use.
Step 4: Create CAM profiles. Honestly, my mill is nothing to write home about. Rigidity is not a strong point. Smart tool paths are the key.
Rough at reasonable margins and finish with levels that you’ve experimented with and know produce good results.
Step 5: Machine
A shot taken during the final finishing cut creating the filet on the edge.
Step 6: Finished Mold
The explanation ends here for now. I’m still waiting on some parts so I’ll discuss the silicone and polyurethane casting afterwards.
Hi Marcham,
That is an amazingly compact shop considering the quality of the molds you are able to produce. How do you manage to keep your computer components from choking on the dust you produce?
I have done a lot of latex and resin molding and casting for my garden railroad buildings, and I used to do a lot of 3D plague routing in my woodworking days. So I am familiar with the general processes involved. I am very interested in your CNC machine. Would you point me at some information about it?
Thanks, Ted
hello,
I bow to a Cad skill far greater to my own, you said in previous posts that you use solidworks is the program you are using for the cnc machine and your lastest designs, I use Turbocad could you post your files so that i could try to import them into Turbocad i would love to see a manipulable projection
Thanks guys!
Haha, I pretty much just let it choke. I vacuum quite a bit but the tiny chips that come off while finishing still get everywhere. Every once in a while I’ll give it a good blast with canned air.
For info on the mill check out zentoolworks.com There is plenty of online support for getting the thing up and running and the customer service is very good.
Thanks, man. I’ll post when I get home tonight.