153 replies to this topic

[PyroSam]

Hi cooperman435,

Wood is cheap and easily available. Also I think many more have access to a table saw than they do a metal cutting bandsaw. Al welding capabilities aren't common at home either, though it's easily farmed out. Most everyone can glue and screw at home though. It may be a simple woodworking project - one could even cut dados in the wood and use t-slot inserts for the sliding bits and the inserts could easily be cut to length with a hacksaw. I'm also wondering if the two bearing blocks are really needed - what about those teflon magic slider thingies Lloyd uses on his ball mill?

At the current time, no I'm not up to writing the control software. If we can't find someone who can though I can make an attempt. Years ago I used to do some PowerBasic programming and moved on to C and C++ and even did some assembler for some Motorola 6800 series processors. It's been 20 years since I've done anything though and like everything else in life, if you don't use it, you lose it. I'm sure I could learn it but it's a huge effort for one small application so I'd rather just find someone. If I have to learn it though I'd rather build it myslef so if I'm unsuccessful no one else is out any money.

I seriously think this would be duck soup for an experienced programmer though - we just gotta find one. Maybe start poking around the CNC hobby forums? Heck, if worse comes to worse, maybe hire a programmer?

[parabolic]

HI,

I control CNC machines at work for maching engineering metal parts, but the programing can't be used for pasting shells as the axis movments are so different.

I think the answer is like what you said before Pyrosam.... is to learn or find someone that can program PIC chips, these will run stepper motors and do all sorts of amazing things. I been trying to learn PIC chip but It's not easy for me!

one thing I can help with is if anyone wants me to build anything in 3d for them, If you send me drawings/rough sketches I can put them into CAD, 3d model format, and see wht it looks like, unless you can do this already?

phil, if you need me to make somthing up let me know, may save you a lot of time cutting things up for no reason.

atb, Lee

Edited by parabolic, 10 July 2012 - 11:28 AM.

[digger]

Yep PIC Micro's are the way to go.
You don't even need to know assembler these days if you buy a high level developement system. I learned assembler before buying the following dev tools:-

Dev V7
C Dev Studio
Dev kit with nice IO

The assmebler knowledge has been useful for slimming and speeding the finished code (although it would not be necessary on this one).

I worked out the algorythm for the WASP some time ago. I do not have any time however to do the PIC dev work as I am full up with other projects at the moment.

Edited by digger, 10 July 2012 - 02:22 PM.

[PyroSam]

Hi Parabolic,

This one is being ran off of Mach3 CNC pc software:


The original machines are running off pc software also - modified versions of Peter Norberg's software (which I believe on his site he said was originally written in PowerBasic).

Basically, from what I gather, the left motor is constantly driven at the direction and same speed for a set distance - a distance calculated by the number of layers and the diameter of the shell. The right motor is also ran in the same direction and for the same distance but at certain intervals simply has it's speed offset to cause the paper to skew..

I've started a CAD drawing but haven't gotten far simply due to time constraints, as I get further along I'll post back.

[digger]

This one is being ran off of Mach3 CNC pc software:

The original machines are running off pc software also - modified versions of Peter Norberg's software (which I believe on his site he said was originally written in PowerBasic).

With a PIC you would not even need to have a PC. It is dead easy to write software for a touchscreen display for the basic inputs required.

[PyroSam]

Hi Digger,

Easy is relative to one's skill set. Though mine included programming years ago, it was just that - years ago and if you don't use it, you lose it. I'm very short of time for the next several months due to a project at work so I have zero time to re-learn programming.

The originals run off pc software but I've heard the Chinese are now using this type of machine in their smaller factories (the larger ones seem to use the spinning hoop design for some reason) and they do indeed use a small console rather than a pc to run the thing.

[parabolic]

I don't have time to learn PIC from scratch at the moment but, I think it might be worth asking a few people in the online PIC forums if anyone can help making the program.

You will need to supply them with a flow chart so they see what needs to be done to achieve the result. The only problem I can see is if it doesn't work out in practice, then debugging will be difficult if you don’t understand PICS.

Again, I may be able to help somewhat as I do have necessary hardware for writing PIC's I have the PIC KIT 2, + software, so if someone gives me the assembler or hex file, I can write it to a chip for you.

PICS can be had for £1 - £15, I’m pretty sure a PIC costing around £2-£5 will do the job.
The PIC will have A/D converts, EEPROM, Timers, many transducer inputs/outputs (ports)

My PIC programing board is limited to certain types of chip/pin count but should not be a problem for this job. The very basic PIC chip will handle pasting shells.

After all it’s only continuously rotating in one axis then rotated a little in another axis every full turn to overlap the tape. A few sensors needed to give feedback on thickness of the wrap, or thickness could be assumed with a calculated time. Perhaps some tape tension sensor and adjuster output?

Lee

[Arthur Brown]

[PyroSam]

Those machines are interesting but if you ever fired shells produced by one you will definitely notice a difference between them and hand or WASP pasted shells.

It's nice you can paste with the fuse in it but it leaves "holes" at the poles. You could remove the shell and rotate it for the next layers to alleviate that I imagine though if you left the fuse out.

I read on one of the forums a while back though that they are also covered under patent (Chinese - Liuyang Fireworks Co, Hunan China is what I have in my notes) and a Patent Cooperation Treaty application had been made. This doesn't automatically grant an international patent (as they don't exist) but it does establish some claim and could be a hurdle (though probably not - I don't think the Chinese are too concerned with hobbyists).

It doesn't appear trivial to build either and would probably still require some computerization to keep track of the layers and stuff.

All in all, I prefer the WASP design.

There's more than one way to skin a cat though and it's interesting to see what people have came up with! Thanks for sharing!

[PyroSam]

Hi Parabolic,

Yeah, that's where I'm at - it's not that I couldn't, nor am I not willing, to learn PIC programming it's just I have zero time for a while due to a huge project at work.

I'm thinking a suitable programmer may be able to be found in the PIC hobbyist forums too but it'd just be nicer if we found a programmer who was also a pyro - they'd just have more interest in it I'd think.

Along these lines, we may have some help. I've had a couple a private messages. We'll see how they develop.

A flow chart of what it needs to do is a GREAT idea! I have a general idea but Digger said he had the taping algorithm worked out - Digger, could you expand on that or perhaps develop a flow chart for it?

From what I've deduced it makes almost a full revolution but stops short and skews - it doesn't overlap the last wrap at all, it skew by more than one tape width. Eventually it covers the whole shell and then it overshoots the pole which creates a new axis/pole to rotate on and it starts over for the next layer.

There are no sensors on the original, and again - no ones complaining about how it works. It appears to work off a mathmatical formula rather than sensing the ball size - see the Operator's Manual I linked to in an earlier post.

I would think some sort of sensor to show when it runs out of tape would be in order though - that is the one complaint I've heard, the shell didn't get fully taped and just kept running so they didn't know how many layers were down when it ran out. You'd think youcould pull the dry tape through a box with a light and sensor to sense when the tape runs out, once it does the machine could be instructed to puase to allow you to put on another roll of tape and stick it to the tail of the last roll (since your sensing before the tape is wetted there's plenty of tail left before it gets to the shell).

[PyroSam]

That is a little different machine - the one I've seen a video of held the shell at top and bottom and left two holes and did not rotate to move those holes. The pole holes in the WASP machines are only one layer thick so they are of little consequence.

The Chinese are still doing some hand pasting and are using WASP clones also, as well as these machines. There's a descernable difference in the breaks of the ones using this type of machine - look at some video in slow motion and it's clearly visible.

Of course that's with product using the machine that holds the shell at each pole and doesn't ever rotate the shell as the machine in the video above is doing, maybe this machine is overcoming the short comings of the one the Chinese are using.

It still doesn't appear to be a trivial machine to build. The WASP would be pretty simple for even the most modestly equipped metal shop to build.

[digger]

A flow chart of what it needs to do is a GREAT idea! I have a general idea but Digger said he had the taping algorithm worked out - Digger, could you expand on that or perhaps develop a flow chart for it?

I spent some time doing the maths to develop an equation to describe the wraping of the shell. I don't think it is the exact algorythm that the wasp uses as that seems to have a few short comings (I know, I own two WASPS).

I don't really want to divulge the equation because it is on my future project list for developing a microcontroller (I will be needing many more WASPS before I am finished). I have a few other PIC projects that I am working on at the moment that are more important to me (even they are falling behind due not being in the country much recently).

It is after all only a geometrical problem, so that maths is not too difficult. Even so it took me some hours of thinking to work it all out.

I may be able to drop in a simple flow sheet for you to work the maths out for yourself.

Cheers

G

[PyroSam]

Any help you can be would be much appreciated Digger!

[the omen]

gareth

what made you opt for pic as a micro controller for your work as opposed to other mcu's?