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 New Dmoco 6 Axis Rig Driven by DMC16 
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Post New Dmoco 6 Axis Rig Driven by DMC16
I have posted a few things in various places on a new rig i am building so i thought i would pull them all together in one thread. Lets hope it doesn't get as longs as the Robot arm one which funnily enough resulted in absolutely zero been made :D
The rig is mainly for animation i dont really do timelaspe anymore but thought it would be of interest anyways just from a rig building point of view.
Quite a few of the parts are salvaged from a old multiplane rostrum camera and therefore are quite substantial . Not at all suitable for easy transport but thats what the client wants . Its going to be used in a large studio so size weight not a issue .
[flickr]Image2016-02-22 11.32.58 by D 1, on Flickr[/flickr]
Slew bearing !
Its driven by Dragonframe and a DMC 16 https://www.dragonframe.com/store/DMC-16.html which allows real time moves . Not to much info about the DMC out their so this may also be of interest . First of all its not that cheap £1541.83 UK :( Build quality is very good but ours did have a slight blemish to the front bezel . But that is a minor complaint .
[flickr]Image2016-03-21 16.33.55 by D 1, on Flickr[/flickr]
DMC 16 inside
You can control 16 channels plus DMX their also inputs and outputs for limit switches etc . I will go more into this as i build the rig .

So far i have built the control box and the pan tilt roll head . Which is a beefed up and improved version of my old design .The control box as 8 channels twin power supplies fans and power monitors . The power monitors give a good indication of the state of things and all is well .I have also tried to keep the data and voltage sides separate to reduce the chances of interference . Their are also EMI/ RFI filters and chokes built in yet again to cut down on interference . I do know of a case were a rig was creeping do to electrical interference in the studio so trying to avoid that one .
[flickr]Image2016-04-15 12.19.16 by D 1, on Flickr[/flickr]
[flickr]Image2016-04-22 17.06.34 by D 1, on Flickr[/flickr]
[flickr]Image2016-04-22 17.06.58 by D 1, on Flickr[/flickr]
[flickr]Image2016-04-15 12.37.11 by D 1, on Flickr[/flickr]
DMC and Motor driver box 19ins Rack mounting .
Theirs 8 CWD556 stepper drivers in their https://www.cnc4you.co.uk/Microstepping ... olt-CWD556 which i quite like and are working well. No heat been generated in motors or drivers .
Just on with track and revolve at mo . Its really heavy i cant lift it myself but as i said its for studio use so at least the weight means it wont be kicked easily .
[flickr]Image2016-04-22 16.53.51 by D 1, on Flickr[/flickr]
[flickr]Image2016-04-22 16.54.02 by D 1, on Flickr[/flickr]
Well thats it for mo just ordered ali for boom will do a bit more testing of the DMC now the control box is up and running
D1


Fri Apr 22, 2016 12:55 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hi D1 As usual very nice attention to detail. You won't be accused of under-engineering on that track drive...

I hope you don't mind some comments?

Those PSU fans will be quite noisy - on a similar type I fitted a simple speed controller as used with old style computer fans. It takes the edge off the noise, but still enough cooling so long as the PSU is not flat out.

It's good to see an EMI filter fitted - though the PSU's have inbuilt EMI filters I believe... creeping of axes is generally caused by a ground loop or bad ground connection.

To improve cooling further consider mounting the exhaust fan on the side rather than the back. You might then get more efficient cross ventilation, also important for the drives.

Another trick for the drives is mount them on a heat plate - a sheet of 6mm aluminium will help to sink the heat from the drives... especially when they are packed so close together...

I don't see any switches for disabling the drives - perhaps that is still planned? It's pretty annoying to have to shut down the whole box when you need to connect or reset a motor.

The USB connector at the back is intriguing. Is that intended for a remote function?


Fri Apr 22, 2016 5:48 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hi Gerald constructive comments are always welcome thats why i post . Its easy to get things wrong when you to close to a job so second pair of eyes always welcome .
Yep fans are noisy Big on at rear is fine hardly any noise at all . As for power supply ones they do alter from noisy to very noisy depending on how much current is been drawn :( That been said they are in the case and that is mounted in a quite substantial 19ins rack flight case . This is why fans mounted at back to side fans would be no good when fitted in flight case .
Yep thought the power supply's may have EMI built in but wasn't sure so the belt and braces approach as been applied .
Think all the fans are belt and braces to ran the box for three days continuous and no heat at all . But their again i have been in studios that get very hot do to amount of lights . Actually thats changing to with Leds etc not as toasty as it used to be.
No switches per drive its taken a long time to build the box as it is . I also worry the more connections/ solders their are the more chance of issues . The power monitor created more joints but thought the benefits outweighed the disadvantages .
Their is a USB at the front not back . Thats for the inbuilt Arduino Mega if it all goes pear shapped with the DMC you can always revert back to stop frame mode .
Belt and braces again :D
Yep track well over engineered think the rack and pinon is unnecessary belt would have been fine .But we had it so we are using it and as i said it does add a lot of mass to the rig
D1


Sat Apr 23, 2016 12:44 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hi. I think if you can add the switches it would be much appreciated by the end user. In fact I would view it as a necessity.

Imagine you are running a shot in realtime to get a preview. One of the motors stalls so you need to reset it. The quickest and neatest way is often simply turn the motor off and move it manually to a home position, then re-zero in software.

If you had to move it using software first, and it had limits set, then likely you could get stuck, aside from the fact it just takes longer and is more fiddly.

Another typical situation is removing a motor temporarily, like a lens motor when the camera has to be removed - and then you need to unplug the motor temporarily - do you really expect them to de-power the whole drive box, which will likely result in having to recheck and adjust all the other motors - given the stepper habit of ticking off position when de-powered...

Anyway - as a daily user of moco gear I could go on - I really hope you get the idea and reconsider - for your clients sake atleast..!

Cheers G


Sat Apr 23, 2016 1:15 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hi Gerald maybe next time on the channel switches . I dont think its that much of a problem i cant see why any of the motors would stall out on a realtime move .
The DMC wont let you run a move beyond the limits of the motor . This is set up well before any moves are built in the axis configuration
[flickr]ImageScreenshot (241) by D 1, on Flickr[/flickr]
You get a balance between acceleration and top speed without stalling out and save it . The when you build a move if theirs anything that is beyond the limits of the motors yellow bands appear on the timeline .
[flickr]ImageScreenshot (239) by D 1, on Flickr[/flickr]
You then adjust the key frames or beziers on the time line until the yellow bars disappear . The timeline updates realtime as you fiddle.
[flickr] ImageScreenshot (240) by D 1, on Flickr[/flickr]
Keyframes adjusted slightly hey presto yellow bars gone . Motors wont stall out you can run the move with confidence .
I can only see stalling issues if something catastrophic happens like coming into contact with the set and it thats case i would reset everything and start again anyways .
On a less controversial note me nice flightcase . Room for another driver box and their is talk on mounting a Mini Mac in its own 19ins rack caddie . If it was me i would just use a laptop but each to his or her own .
D1
[flickr]Image2016-04-23 18.12.59 by D 1, on Flickr[/flickr]


Sat Apr 23, 2016 11:36 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hi D1.

Mantis also has reports of max vel and accel rates for a move, but at best this is only an indication.

Stepper motor limits are not finite or consistent. The motors may have a maximum speed but may not reach it if accel is too high. Even that is not constant - steppers have more power at low rpm so they might be able to accel at some decent rate up to a certain speed, then above that speed the accel must be reduced. So its complicated, and in most cases you really just have to suck and see if a move will run. Not to mention some-one will always want to try and push it a bit faster.

Anyway, there dozens of other reasons motor can and will stall at some point - for example something got in the way of the rig? You change a lens which happens to be a bit stiffer etc... the software can't protect against everything... Murphy's law applies in full.. :)

BTW - what is the main processor board in that DMC?


Sat Apr 23, 2016 5:16 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hello i will let you know how good the DMC is at predicting stall out . But i think it should be ok the rig is quite quick . To quick in fact for safe use so its ships in standard speed. But i will hide a fast mode which is their if they need it but i wouldn't recommend it for your average animation shoot . They tend to have quite slow moves anyways .
Think the best solution for the error issues would be some sort of absolute encoder which just resets everything frame perfect rather than spending time with channel switches . But not enough money in this job for that . I gave a very reasonable price because it seemed a fun job but not much room for extras though :( .
As for DMC board it looks like a custom built item. I did post a photo if you look at it on flickr you can zoom in .Wont tell you much though
D1


Sun Apr 24, 2016 1:38 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
WOW! I go away for a little while and come back to find this. Amazing, impressive rig. Beautifully made. The controller box is amazingly beautiful. Its the nicest looking one-off I have ever seen. Very nice attention to every detail. This will definitely encourage me to work harder on presentation. The slew bearing is also really nice if I didn't say so when it was posted before. Your stuff was always nice, and an inspiration to work harder on my own stuff, but this is really beautiful. I feel like such a slouch by comparison. Hope you don't mind too much if i steal your plan for the driver box. Nothing I have made is anywhere near this nice looking. Great job! Very, very impressive.

Gerald, your advice is wonderful, I will try to follow the advice you give others on this forum as well as what you tell me personally. I love the way Mantis allows manual control of the rig without modification by plugging encoder boxes into the Mantis controller. This ability to run computer control or full manual will help us to lease rigs. it opens up new lease opportunities for us like concerts and sporting events which do not lend themselves so well to the way computer controlled moves need to be planned in advance. Thats something I don't see on DMC-16, which is basically a stopmotion controller with the ability to go fast at times. Its great for what D1 does and I'd imagine most of his customers are already familiar with Dragonframe, so it makes more sense there. More of an apples and oranges thing. I have used Dragonframe a lot, but think Mantis is a more versatile controller for realtime. Having both is awesome though.

Glad this stuff is not a competition, because I'm feeling way behind now. Congrats on the awesome build.


Sun Apr 24, 2016 5:15 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hey driver box a bit of a knock off from Doug anyways . Laser cutter just gives it that bit of a edge . Literally usually polished :D
Slew bearing a one off will be lucky to get my hands on one of those again :( But at least its been given a new life .
D1


Sun Apr 24, 2016 6:55 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
WHAT? KNOCK OFF! That's it i'm gettin me a lawyer!!!

DMAN, that there rig is a thing of beauty! I'm with Gerald about those disable switches for the drives. As soon as I get to the store I'm putting some on my rig ASAP! Not gonna worry about putting in pretty lighted switches, just gonna use a label with ink. Keep it simple. God that is a nice rig. Question though, you have the rack vertical? Wouldn't it be better horizontal? That way the motor can be pulled into it and more easily adjusted? Just curious. I have a rack and pinion that I am thinking of using on another rig so that is why I ask.


Sun Apr 24, 2016 4:39 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Oh dear i have got myself into international industrial espionage now. The only winners will be the lawyers :D
I seem to be in the minority about the switches but its to late now and their just isn't enough money in the job.Neat wiring takes ages and i defiantly under charged.
As i say maybe next time .
Yeah rack i was in a bit of a debate to . Mark Roberts have theirs horizontal which made me think . The pinion gear is spring loaded as on revolve actually so you dont need access to the other side of the rack . The spring takes up any miss alignment between rack and pinion and creates enough contact to transmit drive. Think the only reason tracks are sometimes horizontal is to help stop crud been caught in the rack . This is not really a issue with this rig as its not floor mounted and its a lot easier the way i have done it .
People say ya can make a slider for a few bucks. Ya can its possible but i also understand why Mark Roberts charge what they do .
D1


Mon Apr 25, 2016 12:01 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hey D1, i'm trying to get a sense of scale, what is the dolly travel on that thing? 4 feet maybe 6? And is it going to be on a cart like the Volo or is it a floor mounted rig? Sounds like a floor mount. As for the switches, got mine in today. Work great but no little lights to say enable/disable. Next time. I understand about the under charge. I have built a few things over the years for people and then after the fact figured out that I should have charged more. Live and learn. Looks really good. Keep the pics coming.


Tue Apr 26, 2016 2:35 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hi Doug yes its hard to tell from photos . Distance between rails is 500mm and total length of track is 2.7 meters . The boom will be just under 3 meters by time the weights etc are added . The intention is to make a Key Clamp scaffolding base for the rig so operating height can be changed from floor mounted to up to set height (42ins in my world ).
Moving it around is going to be difficult but they wanted a tank rather than a race horse. The rack and pinion adds a huge amount of weight and i dont think it offers much advantage over a steel belted timing belt .
The liner rails are good the more weight you add the easier it seems to move . I have left one side floating though just to allow for any inaccuracy in rail alignment.
Did you have to do the same with your rails or did you manage to lock both sides ?
On with boom at mo so mill chomping its way through 15mm ali as we speak .I just let it go all day not quick but it gets their . Bit like me really :D .
D1


Wed Apr 27, 2016 12:46 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Well ya wanted more photos Doug . Ali for boom just turned up so shows scale a bit more . Quite a bit bigger than my old crane
[flickr]Image2016-04-27 13.12.56 by D 1, on Flickr[/flickr]
Yeah thats my living room luckily theirs no Misses Displacement 1 so it can all stay their until it needs to go . Going to miss tripping over it and it will be best rig i have made so far . So will try and have a proper play with it before it goes . Hopefully without destroying my living room :D
D!


Wed Apr 27, 2016 5:06 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hey D1,
that is a tank no doubt. Should work well. I set my rails as follows,
I take measurements at both ends to be as close as possible. Then I slip the carriage on. Using a speed square i make sure the carriage is square to one end by loosening one rail. When the carriage moves like greased snot, I tighten that end and move to the other end checking all the way to see if there are any tight spots. As long as the carriage is square to one side the loose side will align itself and everything should move quite nicely. Once I reach the other end it should move with no more than a feather touch. And yes, when using quality bearing blocks on steel rails weight is your friend. The more weight the smoother it gets! Within reason of course.


Wed Apr 27, 2016 7:58 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Doug K wrote:
Hey D1,
And yes, when using quality bearing blocks on steel rails weight is your friend. The more weight the smoother it gets! Within reason of course.



This is quite interesting, Doug. I've been using Hiwin blocks on the track and they are perfect. As you say, it appears that they like to bear some weight, they glide very smoothly.

However, using the same Hiwin blocks on something quite light, like my cross arm, they have proven to be a disaster! I mean, I can feel the little balls as the arm moves from side to side. This causes tiny vibrations.

For this reason, I ditched the Hiwin blocks for the lighter loads and I am using rollers (wheels) instead, much smoother and silent.

Edward


Wed Apr 27, 2016 8:17 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Cheers Doug yeah thats more or less what i did but their still was a little resistance at times. The carriages are very tight on rails as they have rubber cleaning guards . So i will leave one side floating this is standard practice i believe . I have a set of cheap Chiness rails that def have more play but they are fine for my use . As you so weight is your friend to a degree . I can stand on the tank rails and i am not light and i just glide up and not . Much fun to be had / must get out more !.
Hi Edward if noise was a issue thats another ball game . Luckily i am not getting in to that one but i dont think pro rigs are that quiet
Ps Handy explanation on fixed and floating side http://www.igus.com/wpck/6130/The_2_1_R ... rings?C=US
D1


Thu Apr 28, 2016 12:30 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hey D1:
This might seem like a strange request, but I've always wondered what kind of processor they were using in there to do real-time moves. My guess would be the brain is that blue card in the top left of the image you posted? Any chance of a close up, possibly of the underside of that PCB?

Thanks,
David.


Thu Apr 28, 2016 5:15 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
lateAtNight wrote:
Hey D1:
This might seem like a strange request, but I've always wondered what kind of processor they were using in there to do real-time moves. My guess would be the brain is that blue card in the top left of the image you posted? Any chance of a close up, possibly of the underside of that PCB?

Thanks,
David.


On this forum not a strange request at all . When i am next fiddling with the box i will take the lid of again not sure about taking boards out though . If i remember correctly their wasn't much information in their but you may recognise components and layout better than me.
If ya listening Edward this explains your rail problem a bit http://machinedesign.com/motion-control ... ear-motion Solution sounds expensive as always :D
D1


Thu Apr 28, 2016 6:04 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hi D1, This part of the article was quite relevant:

--------------------
Also, bearings circulating inside a linear guide can cause precision-reducing vibration as the bearings transition from “load-bearing” to “nonload-bearing” conditions. Some manufacturers optimize the bearings’ transition-point geometry with specialized high-precision runner blocks to minimize vibrations. For example, Bosch Rexroth’s High-Precision ball rail uses a steel insert with relief zones that dampen ball-entry forces at the ends of the raceway. The result is consistent, extremely smooth motion as balls circulate in the bearing raceways.
-----------------------


I have Hiwin and also another brand. I find the Hiwin better, but still no good for very small loads. Even just having two blocks in line and moving them by hand slowly along the track, you can feel the bearings. You can also feel some small resistance (friction, mainly from the dust "scrapers" - oil seals) but that's OK as it's easily overcome by the torque of the motor. As I said, I find them fine with weight, like in the tracking. It also depends on the speed, I think the faster you go, the less you notice. Unfortunately I tend to go slow….

The little V-slot rollers are actually quite good for small loads, I find. At least they are very smooth.

Ed


Thu Apr 28, 2016 12:47 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Also using Hiwin blocks for a milling machine must be fantastic. The desktop milling machines I quite like are the Wabecos, the top end are fitted with linear rails and already converted to CNC. But they cost around 8 to 10 grand!

One good thing about them is that you can use them manually, useful for small things, like drilling the odd hole, or squaring up a piece of metal. I guess a milling pendant is just as useful for this purpose.

I think converting a nice solid bigger mill is a better proposition.

Ed


Thu Apr 28, 2016 12:53 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Yes Ed, me too. I am getting small vibrations from my 12mm cheap Chinese bearings also. Which is why I am going to build a rig using some V-groove bearings I bought. These things are silky smooth. I think the larger diameter linear bearings are better than the smaller. Unless I want to put a lot more weight on these little bearings. Like I said, weight is your friend.


Thu Apr 28, 2016 6:54 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Doug,

I have used both large and smallV-wheels, and I prefer the heavy duty PU ones.

Today I am making 4 V-slot blocks, each block with 4 of the small PU wheels, the equivalent in size to a Hiwin block, more or less. Then the four blocks will go on C-Beam, two on each side and made into a carriage using 10mm alu flat machined plate. This combo is pretty good for lower weights.

Here in the UK I get alu plate precision machined flat (Alu Warehouse) It doesn't cost much more and the flatness and finish is exquisite, plus they protect both sides with white plastic stick on film, good to avoid scratches while machining and helpful to draw your lines with felt pen. Generally regular stock of alu tends to not be completely flat.

Ed


Fri Apr 29, 2016 12:08 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hello i quite like V slot to just find the bearings a little small . You have to be careful not to tighten them up to much . Shame they dont do a 40x40 section with larger groove which would allow larger bearings. Not tried the C Beam yet but looks to have potential . I use the steel wheels have you tried them do you find the heavy duty PU ones better .
I suppose Igus rail would solve the bearing problem but never been that impressed with the slide quality of it.
As for CNC mill i am seriously considering building my own . I find i am mainly cutting 15mm and 10mm plate . It would be nice to have a more work area and traditional mills dont allow for this . So think will go 4060 router route but a beefier version

Will scratch build it so a lot more substantial so should be ok . Long term project though and will still keep old faithful for small pieces.
D1


Fri Apr 29, 2016 1:11 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Well rig going well and should be finished shortly . Track and revolve/swing all done and tested its fast enough but i can understand how you get the urge to make things go faster when can actually control things real time . A few pictures of gearboxes theirs quite a reduction and i think i could get away with less if i wanted more speed . Theirs actually not much force needed to move things so the gearing may be unnecessary but it does give a high resolution which i quite like .
[flickr]Image2016-05-04 19.19.57 by D 1, on Flickr[/flickr]
[flickr]Image2016-05-04 17.42.22 by D 1, on Flickr[/flickr]
[flickr]Image2016-05-16 16.31.22 by D 1, on Flickr[/flickr]

Very poor quality video but it does so the sort of speeds we are looking at not the fastest but will be fine . Imagine a two meter boom on the revolve and think it will be quite scary :D
D1


Mon May 16, 2016 1:06 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hi, D1, a compact looking assy. Is the black frame recycled or are you anodising these days. Video is "private" so unable to view.

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Mon May 16, 2016 10:31 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hi Mike just good old fashioned paint :D Shed a bit full at mo so anodising on the back burner at mo . Thanks heads up on video only just set up a YouTube thing changed a lot since i last used it . In fact cant even access my old channel Google seems to have set a new one up for me !
So your post on new carbon fiber tubes . Seems perfect for a Techno Crane :D


Tue May 17, 2016 12:43 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
DISPLACEMENT 1 wrote:
Hi Mike just good old fashioned paint :D Shed a bit full at mo so anodising on the back burner at mo . Thanks heads up on video only just set up a YouTube thing changed a lot since i last used it . In fact cant even access my old channel Google seems to have set a new one up for me !
So your post on new carbon fiber tubes . Seems perfect for a Techno Crane :D

Ah paint :-) Video working ok now, the movements looks quite fast, with a 2m arm you would want stand back a bit ;)
With the rain coming for the next few days I might get into my workshop. Cambamed a couple of parts and got some stock ready for cutting the parts for a C-Slider Crane look alike. Will get some photos up when I have progressed.
Just tripping over the carbon tubes at present. May attach to ceiling so that I have X-Y for my Servocity head, It is sat on Ali scaffold poles bolted to a beam / wall so only has dolly motion, that means rewiring the current rig unfortunately.

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Tue May 17, 2016 5:00 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Wow, big monster you have there! It plays a symphony too!

I am currently planning to turn some eccentric bolts on the lathe. I found a way, courtesy of YouTube (Tubalcain) to use a 3 jaw chuck to turn an off centre shaft, and I am going to have a go, in steel of course, though I may have a trial run with Delrin. Then I have to make a short male thread at one end, which I will do by hand, as it is a lot easier than on the lathe. D1, this is to be used with 30mm plastic U groove wheels with 8mm inside dia bearings, so much stronger than the Openbuilds wheels

Edward.


Wed May 18, 2016 5:54 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hi Mike dont mention tripping over things my living room is full and i want my house back :( Look forward to see what you come up with all your bits .
Hi Edward our minds are on the same thing i have been looking around for wheels but to no avail. If ya willing to share i would be grateful. As for eccentrics i have solved the problem in a different way . I can CNC them out of 15mm ali plate you basicaly end up with a bigger version of Openbuilds eccentric. The one i have planned as a 8mm bore a 10mm deep nut with shoulder then a 4mm deep eccentric round bit . All milled with a 6mm bit . You really should consider putting a weekend aside to get your mill working it will save you time in the future.
Me rig plodding on slowly just put some zero markers on the crane axis. I could have fitted my optical gizzmo in here but as cant do on the head theirs no point.
[flickr]Image2016-05-18 15.59.17 by D 1, on Flickr [/flickr]
[flickr]Image2016-05-18 15.59.49 by D 1, on Flickr [/flickr]
D1


Wed May 18, 2016 10:07 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hi D1, I got my plastic wheels with bearings from Ebay, from Poland, you can't miss it, there aren't many. It's my second order and it took about 5 days to arrive. The guy even emailed me to wish me success with my project, which is a nice touch. About 3 quid each.

I am surprised you can successfully CNC an eccentric with a mill, but I'll wait to see your results and I will share mine when I do them.

Ed


Wed May 18, 2016 10:59 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
edward wrote:
Hi D1, I got my plastic wheels with bearings from Ebay, from Poland, you can't miss it, there aren't many. It's my second order and it took about 5 days to arrive. The guy even emailed me to wish me success with my project, which is a nice touch. About 3 quid each.

I am surprised you can successfully CNC an eccentric with a mill, but I'll wait to see your results and I will share mine when I do them.

Ed


Cheers Edward i found those but not quite the profile i was after . Actually just after a larger version of V slot wheels as these will run in standard Rexroth too . So a larger wheel could run in 40x40 section . May have to CNC these too but this is for a future project . This is how far i got with the eccentrics . Imagine a sheet of these in 15mm stock . You just machine down 14.5mm to keep them in place then rough cut them out with a bandsaw then face of with a lathe . If that makes sense
[flickr] ImageScreenshot (256) by D 1, on Flickr[/flickr]
D1


Wed May 18, 2016 12:29 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
If that's the design you want, you could also get hexagonal bar stock and turn it on the lathe off centre, then drill the hole, then part. Although I can see how you can also CNC them, although your method of separating them at the end with a bandsaw sounds a bit long winded and maybe harsh…

Regarding the wheels, if you are just after a similar thing to the Openbuilds with the edge chamfer, but bigger, how about getting flat, solid ones and just chamfering the corners on the lathe?


Edward


Wed May 18, 2016 3:01 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hi With a 2 meter arm I think the main challenge will be programming carefully so it doesn't vibrate or wobble... :o

Look forward to seeing how it behaves.. BTW - Have you considered the option of a shorter arm? Might be cases where it will work better that way. Ideally you could make the arm in two sections with an adjustable parallel arm... G


Wed May 18, 2016 9:03 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
geraldft wrote:
Hi With a 2 meter arm I think the main challenge will be programming carefully so it doesn't vibrate or wobble... :o

Look forward to seeing how it behaves.. BTW - Have you considered the option of a shorter arm? Might be cases where it will work better that way. Ideally you could make the arm in two sections with an adjustable parallel arm... G


I would love for it to have a shorter arm but its not my rig . I have always thought the future was smaller rigs for animation but i seem to be alone on that thought .
I take on board your concerns about vibration and wobble but as always remember this is a stop frame animation rig . If they live moves as small issues it shouldnt be a problem in stop frame :D
Been doing more runs with the DMC the yellow safe bands are a little to safe ! . If you set a max speed in motor tuning the yellow safe zones will not let get near them . In my opinion theirs a bit to much of a safe margin but i suppose theirs no chance of the motors stalling out . Their is a work around for this you simply increase the motor tuning speed beyond their real limits but this then makes more chance of stalling out :(
D1


Thu May 19, 2016 12:04 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Don't really see the problem re the limits. Do they actually prevent the rig from running? Can't you just take them with a grain of salt, and ignore based on your judgement?

Re "it's only for animation" - yeah sure... Ha ha. In any case they'll want to run shots in real time for preview, and maybe shoot some smoke plates or other real time elements? If they can go faster they will try at some point... :)


Thu May 19, 2016 12:36 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
It is a animation company ! thats what they do . But i dont think real time moves will be totally unusable anyways but its not the major concern . In this case the show requires long big moves from high to low hence the length of boom .Iam sorry it would take to long to explain all the clients requirements in detail but be assured thats what i am working to .
As for boom length i have future proofed it . Rather than having joins i have made all the fiddly bits just bolt onto standard stack box ali tube . Which is quite rigid actually . So if a shorter boom is needed you just reconfigure with shorter box section (quite cheap to).
Anyways boom end in pic just bolts onto any length box .
[flickr]Image2016-05-19 09.46.34 by D 1, on Flickr[/flickr]
D1


Thu May 19, 2016 1:06 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
I needed larger eccentrics too. I made mine out of cast plastic. Took a nut and a little piece of rod and stuck them together with modeling clay. Made a mold of that, cast it, then drilled the hole off-center in the cast part. Second mold is of the part with hole. Cast a dozen of those before making a bigger mold with a dozen cavities so I can now cast a dozen eccentrics in one go. I wind up with plastic eccentrics, but they seem to carry enough weight for me to ride on the trolley. I also put one of those locking washers with many ridges between the eccentric and the frame. This digs into the plastic so the eccentric doesn't move after its tightened down.

I used eight skateboard wheels under the trolley with four more running on the sides to keep the trolley running straight on the track. I have a big NEMA 34 motor running 48 volts and direct drive to a 20 tooth timing pulley but would prefer more speed for realtime capture. I got a larger 60 tooth pulley which will hopefully triple my speed but have been working on the P/T head for the new rig the past week so don't know when I will get to run the trolley with the new pulley.


Fri May 20, 2016 7:45 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hi SL, if you do any more plastic casting with rubber moulds, I would love to see a video of the process. I seem to remember you posted (or was it somebody else?) a video in the past. It seemed like a bit of a tedious process…but maybe worth it?

I like the idea of using a 3D printed output as the initial mould to make the rubber mould. Since 3D printing can be slightly rough, I guess you need to sand it and prepare and maybe even prime it so it's absolutely smooth.

Let's hope that 3D printing technology advances so much that soon we will get perfect prototypes on an affordable desktop machine.I went to a massive 3D printing convention here in London, with all the latest machines on show, but none of the filament based printers convinces me, although the resin printers (SLA) were better but had some issues too. I use the equivalent to Shapeways in Europe, that's a different process,(SLS) with the fusion of fine plastic powder, still a bit rough, but quite accurate and reliable, though it needs some finishing.

Edward


Fri May 20, 2016 8:59 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
edward wrote:
If that's the design you want, you could also get hexagonal bar stock and turn it on the lathe off centre, then drill the hole, then part. Although I can see how you can also CNC them, although your method of separating them at the end with a bandsaw sounds a bit long winded and maybe harsh…

Regarding the wheels, if you are just after a similar thing to the Openbuilds with the edge chamfer, but bigger, how about getting flat, solid ones and just chamfering the corners on the lathe?


Edward


Hi Edward sorry i missed that post . But yes think thats the traditional way of making eccentrics . I just hate using my lathe it never goes well . I am still waiting for Axminster to get their stock levels up again so hopefully will have a new lathe soon . But even with a new lathe it would be a laborious process making a decent amount of eccentrics . I will stick with CNC approach, i can watch my plants growing whilst its busy doing what does :D Had a re think on getting then out of plate i just flip the plate and mill in general area of each eccentric to free them .
Casting? not sure if theirs enough strength that . I do a lot of casting and it as its limitations.
Back on rig front PT head all painted and finished . Its quite speedy and could be faster theirs enough pulse rate coming out of the DMC to down the gearing and up the micro stepping and still have a decent resolution . But has rest of rig is not as speedy not much point really . Next time maybe ?
[flickr]Image2016-05-20 17.06.24 by D 1, on Flickr[/flickr]

D1


Fri May 20, 2016 10:17 am
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