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Decimator - Team Demon - NSW (download limits beware)
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Glen
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Decimator - Team Demon - NSW (download limits beware)

A few of you mentioned it was a task trying to find info in my previous build thread. So decimator is recieving his own uncluttered thread. Enjoy Wink

SPECIFICATIONS

Weapon: 4kg 350mm one tooth blade at 7500rpm. Made from 12mm everhard 400 and driven by a scorpion 40mm brushless at 1.8:1 reduction.

Drive: Banebots p60s 16:1 with 775 motors run on 6s. Using blue style 4 inch banebots wheels and hubs.

Electronics: 150A brushless controller and 2x tz85s for drive control. 6s 3.7ah a-spec turnigy lipo battery.

Armour: 4.5mm hdpe top and bottom cover and 5mm everhard 400 frame


So here we go!

My original plan for a 2nd robot was a compressor powered flipper. I was expecting work to quieten down in the 2 months leading up to the event, leaving me with lots of time to fabricate all the components. As always seems to happen things went the opposite way and very little time presented itself. Especially for fabricating a robot that would have been as complex as i had hoped.

I got as far as you would have seen in the other thread. Some parts turned and drilled but by that time it became clear it wouldn't be possible to finish it. I spent a further week working on an alternate design before ruling that out as too heavy as well and decided with 4 weeks remaining i had to just revert to what i know best to get something done.

MASSIVE SPINNERS Laughing

For so long i wanted to make a clone of my beetleweight killer in feather scale. But that would have needed a fair chunk of money for the waterjetting, lipos, brushless motors, huge pieces of aluminium etc etc and tools that i never had such as the mill and rotary table... until now.



So in a night the design was roughed out. Having worked out the weight would be exceptionally tight but do-able, the design was cut down some more the next night into its final incarnation. Then it was all off to the be cut!

I didn't want a grenade robot that had all its weight points placed in one area. Decimator needed to have strong drives, a powerful weapon and good armour.



Laser wizard cut the plastic HDPE top and base in 4.5mm while Australian Waterjet Cutting did the rest in 5mm everhard 400.

In the mean time, as many parts as possible were made without having any of the frame or weapon. A very different way of making a robot to the ways i'd gone about doing it in the past which was just making the parts to fit as the robot build progressed.

The astute of you might have noticed the frantic rush to get the laser cutter working again roughly around when decimators build started. The reason for that becomes clear later but for now heres a teeny tiny scale model. The holes in it are less than 0.2mm diameter Very Happy coolness!



This is a very useful method for seeing if your dxf files are good before you send them off to be cut in steel. A couple of issues were caught this way that would have been seriously problematic had they made it into the final robot.

The first parts turned - The end caps for the weapon axle. Designed to stop the axle ripping out of the frame, so an ultra stiff but light piece is needed, An m8 socket head bolt sits in one side and a turned down m8 coupling nut sits in the other.



Next up is the weapon mount. The design is a direct clone of killers. Two slots on either side with a bolt and nyloc in them. This lets the whole motor assembly slide foward and back for belt tensioning. However the slots needed to line up perfectly with the waterjet cut holes in the frame i didn't yet have and without a DRO that would have been a seriously tedious and difficult task. Not so with the laser.

The aluminium mount was turned to size and a few mdf jigs were used to transfer the holes and slots to the metal easily. It ended up fitting perfectly so i guess that is a success Smile



The completed mount, axle end caps, a test axle and one of the frame braces all done. The base of the motor mount is very thin at 2mm to save weight, but the brushless motor presses in tight to support it. From what i saw it didn't bend even after having the motor ripped out so all seems okay there.



Lotsa aluminiumynums Shocked 110mm 6061 for the weapon hub and pulley and the other bits for the motor pulley. All fresh from ebay. The local places couldn't get me anything other than 2011 grade for cheap.



In a tribute to wastefulness i just turned the 70mm odd diameter motor pulley from 100mm metal. I used the other bit for a non robot related project and it needed a 70mm stub to locate it. So there was some method to the madness.



All turned - this took way too much thought as the lathe couldnt actually get that angle at that diameter. The cross slide of the lathe had to get reversed and the toolpost used on the opposite side with the chuck running in reverse while i reached over to twiddle the compounds wheel Laughing Can't say it didn't work though



Choppy choppy. I seem to do alot of awkward cutting like this. Need to do some mods to the bandsaw to make this easier me thinks. Would also like to extoll the virtues of the bandsaw at this stage. Everything you see here on in was done after 9pm. So quiet!



After putting it back in and facing/boring/turning the other side this is the wastage. Now you see why i am keen to get an aluminium smelter happening.



The pulley took quite a few tries to get the press fit right. Must have had to clock it up in the 4 jaw chuck at least 6 times before it was good. Added 6x m6 holes for grub screws however if the pulley came loose with time. Weight savings too. Also rotary table. So much rotary table.



Tadahhh Very Happy This looks heavy as lead but it is astonishingly light. The whole lot is about 500 grams. Very happy with the results.



Was on a roll at this stage so i started demons 2nd drill gearbox right after at about 10pm and got it mostly finished. Funny how you get so engrossed in lathing sometimes.



Thank you to Jaemus for lending me a whyachi switch his spare bearings for catastrophe too. Didn't look like they would show up in time (and they didn't, grr!) so you are a life saver good sir Very Happy

Anyway. That was all done 2 weeks ago. Flash foward to the week before the event when everything started showing up. Panicking now!

The frame showed up from AWC in record time. To say i'm pleased with the service is an understatement. Notice how there is a 2nd blade? So peeved i didn't send that up with Nick as i could have had decimator working again after its huge first fight. I have no idea why i didn't. Sleep deprivation i'm assuming had something to do with it.




Rushing home on the train with that unwieldy pile, the frame was slapped together with some aluminium blocks i turned down to 60mm exactly in order to keep the top and base set to the correct height while being welded. Seems to all fit.

With that done the lot was tacked together. The waterjetting was so well done the task was exceptionally simple even without any tabs. Trying to keep the heat input down was a big deal to try retain as much strength as possible.

The brace block can also be seen in the middle. This ties the top of the frame to the bottom to make the front end the weapon sits in rigid as well as keeping the top and bottom piece aligned for welding.





With that done its time to make the last of the machined pieces. Didn't want to tempt fate and machine the weapon hub before the disks arrived in case i went to far and turned a rather pricey block of aluminium to scrap. With so much machining to do i had to really just smash through it in record time.

No way could this part have been done in time without the eccentric engineering tool. 3mm depth of cut was easy. Gettin the hub to size only took about 10 passes or so at 1000rpm.




The amount of waste after half the outside of the hub is turned... That's subtractive machining for you.



Anyway i was sick of being pelted with smouldering aluminium so i went back to the frame after it had cooled. Time to button him up proper Very Happy



Very happy with how the welds went together. I used the proper low hydrogen filler as per the manual too and cleaned everything etc. It really does make a difference. The frame was welded over two very long nights. Small 3 inch long patches were welded at a time on opposite corners of the frame before it was left to cool back down to ambient so there was no warping.

There wasn't a single bit of it on the final piece either so very chuffed about that.



Many people say bolt.com.au has turned a bit crap. But my giant convoluted order showed up in usual time for them (aka 2 days). Good times bolt.com.au



Next item was one i dreaded. The holes were waterjetted .2mm undersize in the hope they would come out near perfect. They were close. so close! At about 19.97mm at the biggest part of the taper down to 19.83 or something at the tightest. Was really ripping what little hair i have left out over how to fix it as the fit needs to be tight or else the axle will just flop around.

Fortunately the fix was very easy as the dremel sanding drums had the bores reamed to size in no time. A++ on the that job. Even if the drums cost $35 for 5 (feck you dremel and your overpriced wares btw)



Was a bit iffy about having the axle like this, but weight dictated it be that way. I could have made a machined insert for the axle to sit in but that would have ended up quite heavy. We will see how it goes in the long run.

We're at wednesday night before the event an i am seriously starting to panic haha, so no sleep from now till the event Shocked

The hub is finished after a monster effort. Getting a tight fit on the bit the disk fits over also required a few re-chuckings in the lathe. But even being so tight on time i wasn't willing to half ass any of this. It had to be perfect. In the end it was so Smile

Two 20mm dual row angular contact bearings go in the hub with an aluminium crush tube between them. Some .1mm shims can be used to adjust the height of the crush tube for efficient running. There is 10x holes in total in the hub. 5x are tapped for m8 to hold the disk on and 5x are drilled and reamed for 8mm hardened dowel pins. I didn't run with the dowels due to weight concerns and i dont think it needs them. But it's good to future proof.




The picture taking slowed for obvious reasons and i didn't grab any pics of the main pulley being made. But here's some pics of the complete item. The pulley is a light press fit over the hub (once again taking a few re-chucks in the lathe.. getting real good at that btw) and has 16mm holes bored into the bottom for both weight savings and for the heads of the bolts holding the disk on to sit in.



Ruh-ruh-rotary table <3



Now some trickyness. The original plan was to retain the pulley with a huge 70mm circlip. I'd checked bolt.com.au had them in stock but also neglected to check they cost nearly $50 each. So this was born at the last minute. By gawd did it work awesome though.

The entire disk and pulley goes in the rotary table



Using a center drill 3x holes are drilled halfway between the pulley and hub. They are then drilled to the right depth with a 5mm drill. My mill has a rudimentary Z axis DRO that really saved my ass quite a few times. This is one of them.



Countersunk and done. Just needs tapping but i dont have an m6 tap of any description. Dang.



Seems to fit just like the cad. Exxxxcellent Cool



Mwahhahaaa looking evil now. Can see the welds on the rest of the frame. They are fusion welds on the top and bottom as minimising heat input to the frame is the major concern. They got linished off eventually.



The paint, the paint?! *frantic 8:30pm trip to bunnings* You can't tell me the cross section of those holes doesn't look awesome though. Right? Don't appear to have pictures of them once threaded but they look even more epic. Trust me Razz




First assembly of the weapon completed at about 4am wednesday night. I then noticed it was going to be a bastard to get the weapon installed. But oh well, too late for worrying now! Frame is also welded and linished. Love my mega linisher. took next to no time although my neighbours are out for blood at this stage.




Finally starting to see the light at the end of the tunnel. Weapon motor assembly, blade assembly and everything bolted up and spinning free. Unfortunately scorpion did their usual trick and sent me a motor that is wildly different to their specs on the site. This outrunner is nearly 8mm longer than stated, so it didn't fit between the frame panels requiring me to bend the top of the frame up to wedge it inside.

Also had to dremel out the top opening as a result. Thankfully that wasn't too hard. Notice the long coupling nut that holds the axle assembly together. I had 4x of different lenghts so the height of the blade can be raised up or lowered down. The final items are much shorter than shown as well, that one is just as they came new.



Can't find my 2nd reciever for the spare v1 hobbyking radio either. SHIIIIIIIvers. Andrew (welch) to the rescue by letting me borrow his one out of warning. And shambling around at like 9pm for it. You friggin legend ;D

Thursday morning - Thank christ for pod triple strength coffee (i dont even drink coffee, what is happening to me?) Rushed out to laser wizard and with some rather suave begging i managed to get my parts out of them. They came out super nice, only needing a run over with 400 grit sandpaper to press in perfect.




Not going to get the thing done by this stage so the bits are all turfed into the car. A brief expedition into strandbags for a suitcase at 8am later and I'm on the train to work at peak hour.

Yes i am that jerk.



No pics taken but over 6 hours Decimator was assembled, had the battery bay and interior bits machined and drives setup. Surprisingly it was underweight at 12.9kg complete so some small pieces of framework inside were made to brace the top and bottom plastic panels together. I will put up pics of that later Smile



I might actually get this done after all!

Thank you double muchly also to Jake that took the time to grab one of his robots old power switches and run it down as well as helping me wire the thing up. Was so fatigued i couldn't have gotten it done myself. Possibly evident by me soldering the wrong battery connector 4 times in a row. Good job Glen. Good job.

By 2am i still hadn't packed for the 5am trek to the airport. Threw it all in and the bugger weighed like 38kg. Just throw the spares out... 32kg.. out go the tools.. 28kg.. guess i wont be bringing many spare clothes >.>

But i made it. Half alive but there all the same. Passed out at the hotel for the best sleep i've had in years followed by some helping at the arena setup. Sorry i didn't get there early enough to do more, was just so knackered i literally couldn't keep my eyes open D:

Lastly was soldering demon and decimators batteries plus some last minute touch ups to the wiring. Demon also needed his brushless connections made solid as the bullet terminals had worn out.

Soldering in hotel room without setting the fire alarm off 101.



All ready. What a freaking rush to get to this point Shocked Had a well deserved drink or 5 after that.



And yeah, that was the build. Hope you enjoyed reading this as much as i did building the robot itself. Looking foward to what modifications he will recieve in the future as i reckon this is going to be a great base to work from. Watch this space! Cool
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http://www.youtube.com/user/HyzerGlen - Videoooozzz


Last edited by Glen on Thu Oct 09, 2014 7:45 pm; edited 3 times in total

Post Wed Oct 08, 2014 9:38 pm 
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Glen
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Joined: 16 Jun 2004
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Location: Where you least expect


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*event report placeholder post*
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Post Wed Oct 08, 2014 9:38 pm 
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Ellis



Joined: 21 Jul 2012
Posts: 129
Location: Shopshire, England


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This was an amazing read. Awesome, awesome job on the bot. You've turned into a precision machining wizard what feels like overnight. Really cool stuff. Robot needs a passport, the UK is running low on horizontals!

edit: thread title should say NSFW lolol


Last edited by Ellis on Wed Oct 08, 2014 11:49 pm; edited 1 time in total

Post Wed Oct 08, 2014 10:30 pm 
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haz



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I love this thread. So gosh dang hardcore.
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Post Wed Oct 08, 2014 11:35 pm 
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Jaemus
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Joined: 01 Apr 2009
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Location: NSW


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Holy crap Glen,

What an epic build. I shouldn't be surprised, what you could achieve as a penniless hobo was always going to be an indicator of what you could achieve as a cashed up bogan Wink

Well fucking done, super sad that you didn't get to have a) more fights b) your spare disc or c) video of the disaster unfolding, but that's robots for you right
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<Patrician|Away> what does your robot do, sam
<bovril> it collects data about the surrounding environment, then discards it and drives into walls

Post Thu Oct 09, 2014 8:27 am 
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Valen
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video exists
https://www.youtube.com/watch?v=rdams4_Bsc0&list=UUhAMZKeAy7vW2Rtqc-3jHHA

Putting this here for reference
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Post Thu Oct 09, 2014 8:51 am 
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Jaemus
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Indeed it does, and oh boy!
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<Patrician|Away> what does your robot do, sam
<bovril> it collects data about the surrounding environment, then discards it and drives into walls

Post Thu Oct 09, 2014 1:13 pm 
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Eventorizon-GB



Joined: 15 Nov 2013
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Location: Ripon, United Kingdom


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Wow... so much to say but it basically revolves around that whole machine being awesome on every level!
The only kick in the teeth is that it is basically the same as a machine I had designed as my next 'big spinner'.
Got a few questions, what voltage is everything running at. You have your custom drill motors on what I am guessing is 4S, or are they 24V and they and the HK-4035 are all running on 6S? Any chance we can have a look inside?

As for that hit... wow! No wonder they both broke! But that is one of the main reasons that horizontals are a dying breed in the UK, we have an OOTA. It might have bounced back in on the first hit but given ooba-hori's tend to oota themselves people aren't interested most of the time.

Post Thu Oct 09, 2014 7:04 pm 
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Glen
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quote:
Originally posted by Eventorizon-GB:
Wow... so much to say but it basically revolves around that whole machine being awesome on every level!
The only kick in the teeth is that it is basically the same as a machine I had designed as my next 'big spinner'.
Got a few questions, what voltage is everything running at. You have your custom drill motors on what I am guessing is 4S, or are they 24V and they and the HK-4035 are all running on 6S? Any chance we can have a look inside?

As for that hit... wow! No wonder they both broke! But that is one of the main reasons that horizontals are a dying breed in the UK, we have an OOTA. It might have bounced back in on the first hit but given ooba-hori's tend to oota themselves people aren't interested most of the time.


Cheers all Very Happy

Yeah there's only a set number of ways any basic design will turn out when working to a weight limit. Getting it all working in harmony is the tricky bit Wink

I added the specs to the original post. Forgot to whack them in - but to answer more specifically:

Its running a 6s 3700mah A-spec turnigy lipoly and using p60 16:1 gearboxes with the 775 motors along with the blue 4" wheels. The custom drills went into the vertical spinner demon and they worked flawlessly (woohoo Very Happy). One side died pushing ringo around in its second fight so i have no idea what happened there. It's locked up completely. The robot was a bit of a handful to control as it seemed to have zero traction so it's surprising the drive died.

They never turned freely from the day i put them together so i reckon something isn't assembled or shimmed right. I'll see when i get Decimator home Smile

The scorpion runs at 6s due to the gearing being something like 1.8:1 on account of the main pulley becoming too massive to machine. Even so the current is quite reasonable at start up (140a ish) and it starts up reliably.

Will snap some shots of the inside when its home but there's nothing much in there. Just the battery controllers and two drives bolted in Razz

Definitely possible that it'll just explode out of the arena each hit. But if it can destroy a robot or two on the way out that will do me just nicely Laughing Don't think anything other than a good flipper, wedge or drum will do that well over there with such low walls anyway.
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Post Thu Oct 09, 2014 7:41 pm 
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Eventorizon-GB



Joined: 15 Nov 2013
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Location: Ripon, United Kingdom


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Yeah, thats true. The arena has a massive effect on what designs work and which don't, in terms of winning the competition.

Just to compare stats my machine was spec'd quite differently in terms of its weapon. Drive is very similar/identical:

Weapon: 3.5Kg Single Tooth 300mm Disc, driven by a HK 5020 at a ratio of 1:2. (8325rpm theoretical max)
Drive: 16:1 BB with 98mm Wheel (4"), with TZ85A
Power: x2 2600mAh 5S wired to give 10S top the weapon and 5S to each side of the drive.

The construction was basically identical. I would show but the files got corrupted about a month back. I almost lost the models of Conker 3 and Binky!

I am surprised that it drove so badly. Magnets for next year perhaps?

Post Thu Oct 09, 2014 8:17 pm 
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seanet1310



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The QLD arena has a wooden floor. Not so sure magnets will help with driving unless I am missing the point.
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Post Thu Oct 09, 2014 8:33 pm 
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Eventorizon-GB



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quote:
Originally posted by seanet1310:
The QLD arena has a wooden floor. Not so sure magnets will help with driving unless I am missing the point.


Oh, I didn't know the floor was wooden. Ok, that makes that pointless. Rolling Eyes

Edit: Managed to dig out an early version of my horizontal and its basically identical. Disc is different and weighs a little more, and I have Titanium top and bottom plates not HDPE but the rest is very similar. I have also been beaten to using the outside of the brushless to mount the pulley. Though it was probably done ages ago anyway.

Post Thu Oct 09, 2014 10:12 pm 
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Jaemus
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Yeah i think Glen's beetleweight ancestor for this robot, Killer, also had the pulley on the outside of the brushless
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<Patrician|Away> what does your robot do, sam
<bovril> it collects data about the surrounding environment, then discards it and drives into walls

Post Fri Oct 10, 2014 7:49 am 
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miles&Jules
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WIN...Jules and i both said OMG when we saw your neat welds. Very Happy Very Happy Very Happy
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Post Fri Oct 10, 2014 9:00 am 
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Cpnwolfe



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that made me moist. thankyou for updating glen (stealing ideas and drooling over machining starts now!)

Post Fri Oct 10, 2014 3:39 pm 
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