109 replies to this topic

[hereticorp]

zaphodB, on Sep 25 2008, 01:43 AM, said:

I guarantee you that the hotglue won't cool by the time it falls out of the tube.

Thank you for that completely useless comment.

If you have something helpful to offer, please add it, if not, don't post.

[Split]

Can you fix your picture? I had figured out a problem or two with your design and I was going to tell you but now I can't remember. Honestly, I would still stick with my design if I were you. No timing issues and minimal movements.

[bobafan]

Alright. One of you got me thinking.
I have an idea for the dome creation problem.

You have a bicycle chain or something similar act at as a conveyor. Have the chain be on it's sideand on every other link or so, have a small cup the shape of the dome.(you could use a drill bit to make the holes) You would still need an automated hot glue gun and the weights need to be the blank already. The darts start out already weighted, so they should be naturally standing up. First, the hot glue dispenser puts hot glue in the mold. Second, A dart is placed on the glue which is still hot. (you lego mindstorms to make an automated arm or some other method to do this) The chain continues around and when the glue cools, the darts are kicked off by some sort of rotating mechanism.
I will make a sketch and test out the mold idea when I get back from class. It is hard to draw on a laptop touchpad and I don't carry blocks of steel and a drill press around with me.

[hereticorp]

bobafan, on Sep 25 2008, 10:07 AM, said:

Alright. One of you got me thinking.
I have an idea for the dome creation problem.

You have a bicycle chain or something similar act at as a conveyor. Have the chain be on it's sideand on every other link or so, have a small cup the shape of the dome.(you could use a drill bit to make the holes) You would still need an automated hot glue gun and the weights need to be the blank already. The darts start out already weighted, so they should be naturally standing up. First, the hot glue dispenser puts hot glue in the mold. Second, A dart is placed on the glue which is still hot. (you lego mindstorms to make an automated arm or some other method to do this) The chain continues around and when the glue cools, the darts are kicked off by some sort of rotating mechanism.
I will make a sketch and test out the mold idea when I get back from class. It is hard to draw on a laptop touchpad and I don't carry blocks of steel and a drill press around with me.

Ok, so you want me to first add a heated weight to the blank, then drop the blank into a tube that will slide it down onto the mold conveyor, somehow making it so that the hot glue doesn't stick to the mold itself. And then having a knock-off point to drop the finished dart into the hopper.

Not bad, but the problem of keeping the glue hot enough to melt the dart into it while still letting it cool enough to discard the fully created stefan after would be a challenge.

Getting the weighted blanks into place to go onto the mold chain would also be problematic.

I think in the overall doing everything in one place is the best policy for this.

And no mindstorms, no lego of any kind. I'll be using metal and wood and that kind of thing for this.

Splitlip, on Sep 25 2008, 10:05 AM, said:

Can you fix your picture? I had figured out a problem or two with your design and I was going to tell you but now I can't remember. Honestly, I would still stick with my design if I were you. No timing issues and minimal movements.

Picture's fixed. The design in that picture is based off of your design, but it simplified it by removing the line of darts and making the whole system just do one dart at a time.

[Split]

Alright now that it's back up I figured out your problem. When the dart falls in front of the push block it's going to have a lot of momentum and will fall over. I see you have a slant there, but it could either fall onto the slant or fall forward. It will only take one out of the hundreds of blanks this thing will cut to jam up everything.

I solved this in mine with the wedge that moves on the perpendicular axis, but I have an even simpler solution now. Make the push block solid, with a hole bigger than a stefan running all the way through it. It has to have a bottom track, but it also means no side tracks are needed. When the block is back, a blank drops in and stops on the bottom track. The block moves forward and the hole lines up under the tube. This allows for size tolerances not dictated by the dart size. Just make the block's stroke bigger if you need more room to work.

The block is now forward and the hole is over the cooling tube, separated from each other by a sliding door that has to be flush with the bottom of the push block. The push block will hold the blank steady as the weight and glue are dropped in. Door opens, dart cools and is done.

Bobafan, don't get me wrong, yours is a good idea, but it's pretty out there. We would have to weight the dart then spin it and drop it precisely into a 1/2" max diameter cup that we have to machine a dozen of to be exactly the same. The problems just abound. The rotational forces will probably make the weight fly out. If any of the cups came loose from the rotating chain, which uses dozens of pivoting links, it would throw off all of the darts. The size of the project would also increase since now instead of holding it steady and doing glue and weight, you do weight, spin, align, put on conveyor chain, knock off.

[aetherguy881]

zaphodB, on Sep 25 2008, 01:43 AM, said:

I guarantee you that the hotglue won't cool by the time it falls out of the tube.

I haven't quite figured this part out to numbers yet. No one said the conveyor had to be really short. There I'll try to get an idea for the conveyor drawn up for you guys. What I'm working on is that they will be fully completed by the time they drop out. The conveyor is a loose term there. I'm planning on having an individual dart grabbed by an arm while it is vertical. The arms will be on the conveyor. It won't be a standard flat conveyor. It will be on its side.

[hereticorp]

aetherguy881, on Sep 25 2008, 10:52 AM, said:

zaphodB, on Sep 25 2008, 01:43 AM, said:

I guarantee you that the hotglue won't cool by the time it falls out of the tube.

I haven't quite figured this part out to numbers yet. No one said the conveyor had to be really short. There I'll try to get an idea for the conveyor drawn up for you guys. What I'm working on is that they will be fully completed by the time they drop out. The conveyor is a loose term there. I'm planning on having an individual dart grabbed by an arm while it is vertical. The arms will be on the conveyor. It won't be a standard flat conveyor. It will be on its side.

Feel free to design a completely different setup than Splitlip and I are working on, but we've moved completely away from the idea of a conveyor of any kind, much less an arm to grab darts. Too complex.

[bobafan]

Wow. Okay, I totally missed two pages of designing.
I don't think you need my help at this point.

[hereticorp]

Splitlip, on Sep 25 2008, 10:46 AM, said:

Alright now that it's back up I figured out your problem. When the dart falls in front of the push block it's going to have a lot of momentum and will fall over. I see you have a slant there, but it could either fall onto the slant or fall forward. It will only take one out of the hundreds of blanks this thing will cut to jam up everything.

I solved this in mine with the wedge that moves on the perpendicular axis, but I have an even simpler solution now. Make the push block solid, with a hole bigger than a stefan running all the way through it. It has to have a bottom track, but it also means no side tracks are needed. When the block is back, a blank drops in and stops on the bottom track. The block moves forward and the hole lines up under the tube. This allows for size tolerances not dictated by the dart size. Just make the block's stroke bigger if you need more room to work.

The block is now forward and the hole is over the cooling tube, separated from each other by a sliding door that has to be flush with the bottom of the push block. The push block will hold the blank steady as the weight and glue are dropped in. Door opens, dart cools and is done.

Hrm... The problem with that is the dart will fall forward unless you have a block that matches up with the hole in the push block. You'd also have to have some sort of adjustable mechanism if you want to make non-micro stefans.

It's quite a good idea though, and I'll definitely work it into a new design. Integrating the retention clamp into the push block will solve some of the complexity issues that I was contemplating. We can also spring the block so that a motor overshoot (happens sometimes on the cutter) won't keep the block from correctly clamping the dart in place for the BB/Glue stage.

[Split]

How the hell would the dart fall forward? It's in a tube basically. And if you want to make different size stefans, just make inserts. You should have started something by now me thinks. Or at least run the ideas by your dad to see what he can come up with circuit wise.

[hereticorp]

Splitlip, on Sep 25 2008, 01:04 PM, said:

How the hell would the dart fall forward? It's in a tube basically. And if you want to make different size stefans, just make inserts. You should have started something by now me thinks. Or at least run the ideas by your dad to see what he can come up with circuit wise.

If I was actually going to do construction on this right now, that would be true. But sadly I have other things that require my attention and don't let me get into the nitty gritty of this as yet.

Besides, I want the whole idea hashed out and a plan drawn up before I do much of anything.

And it would fall forward if some roughness on the dart caught on the bottom plate that the push block slides over.

[Split]

It wouldn't fall over because it's in a tube. How do you fall over if you're held up on every side.

[hereticorp]

Splitlip, on Sep 25 2008, 03:31 PM, said:

It wouldn't fall over because it's in a tube. How do you fall over if you're held up on every side.

So instead of a pushblock with a tooth in front of it, you want a tube that's somehow both tight enough to hold the blank in place and loose enough for the blank to fall in without snagging and fall out equally without snagging?

I think a groove/tooth setup makes more sense at that point.

[Split]

hereticorp, on Sep 25 2008, 03:39 PM, said:

Splitlip, on Sep 25 2008, 03:31 PM, said:

It wouldn't fall over because it's in a tube. How do you fall over if you're held up on every side.

So instead of a pushblock with a tooth in front of it, you want a tube that's somehow both tight enough to hold the blank in place and loose enough for the blank to fall in without snagging and fall out equally without snagging?

I think a groove/tooth setup makes more sense at that point.

Are you being serious? Ever notice how many sizes brass comes in? Ta da. Why would it snag anyway? It's closed cell foam. The outside has very little friction. That's why we use it in barrels. I really don't know what planet you're on right now. You have the blank cutting in a tube that holds in straight enough then lets it go. Seriously I think you're just trying to show me up for some reason.

And as for the groove and tooth setup, while it works, it's triple as much work, and involves a lot of timing and spacing, whereas a block that takes it from the cutter to the weights is just a stop and start. Do what you want.

You'll kill yourself trying to get the parts for it. I'm a big advocate of having a plan, but for something like this you can't cast every piece exactly how you need it. You need a plan for materials and a plan for how it can all be assembled. The push block can easily be a hunk of wood, but what about a tooth wedge? Wood, maybe, but it will need to be finished off, adding tons of work and measuring (added thickness from the finishing products after getting it into the proper shape).

[hereticorp]

Splitlip, on Sep 25 2008, 04:09 PM, said:

Are you being serious? Ever notice how many sizes brass comes in? Ta da. Why would it snag anyway? It's closed cell foam. The outside has very little friction. That's why we use it in barrels. I really don't know what planet you're on right now. You have the blank cutting in a tube that holds in straight enough then lets it go. Seriously I think you're just trying to show me up for some reason.

And as for the groove and tooth setup, while it works, it's triple as much work, and involves a lot of timing and spacing, whereas a block that takes it from the cutter to the weights is just a stop and start. Do what you want.

You'll kill yourself trying to get the parts for it. I'm a big advocate of having a plan, but for something like this you can't cast every piece exactly how you need it. You need a plan for materials and a plan for how it can all be assembled. The push block can easily be a hunk of wood, but what about a tooth wedge? Wood, maybe, but it will need to be finished off, adding tons of work and measuring (added thickness from the finishing products after getting it into the proper shape).

I'm not trying to show anyone up. It's just a matter of the material being loose enough to slide and tight enough that the BB and dome can form in a consistent fashion. That's all I'm worried about at this point, aside from how I'm going to do the timing so that the appropriate pieces run at the right times.

I'll try it out with brass and see how the falling works along with the steadyness of the blank after movement. I can mock up a decent pushblock without the rest of the materials and see how the drop-in process works out.

I wasn't planning on casting anything, and I was going to use wood for the push and polycarb for the tooth, but I'll try your brass idea first.

I'll let you know how it goes, I should have some time to work on the idea this weekend.

Edited by hereticorp, 25 September 2008 - 03:18 PM.

[hereticorp]

Just Some Bob, on Sep 25 2008, 04:49 PM, said:

If you've thought of multiple ways to do a task, and there's no definite means of choosing between them, build the one which you think is simplest and fastest to get built.

Didn't I just say I was doing exactly that this weekend when I have some time to actually work on it?

I think I did.

[minsc]

Hey guys, I've been reading this topic for a while now. Anyways, I was wondering if something like this would help:



Basically, it would be like cutting x number of pieces instead of one at a time. The blue piece at the end would either be a pressure sensor to trigger a stop of feeding, or just a stopping plate for manual use. Hope this helps.

First post woo.

[hereticorp]

minsc, on Sep 25 2008, 08:39 PM, said:

Hey guys, I've been reading this topic for a while now. Anyways, I was wondering if something like this would help:

Basically, it would be like cutting x number of pieces instead of one at a time. The blue piece at the end would either be a pressure sensor to trigger a stop of feeding, or just a stopping plate for manual use. Hope this helps.

First post woo.

Nope.

Cutting speed is not the issue, and this would introduce some insane difficulties and you will never get even cuts.

We're well past the cutting point here, but if you want to build that for yourself go ahead.

Edited by hereticorp, 26 September 2008 - 08:12 AM.

[Split]

So how'd it go?

[hereticorp]

Splitlip, on Sep 29 2008, 03:39 PM, said:

So how'd it go?

Worked out ok, although it needs to be in good alignment vertically or it can get stuck pretty easily. I'll work on a way to fix this. Probably deform the top of the brass out a little bit so it gets a funnel effect.

Gotta work on the mechanisms for the rest of it, and go out and see what I can purchase in the way of a hot glue delivery system.

[roboman]

You should use one of these for your control system. I've been using them for a few years now, and they are really easy to program, and have 16 I/O pins. Also, you could use servos as your actuators.

[Lucian]

Since this thread just got bumped I thought it would be fun to spend 15 minutes working on a weight adding system (sp?), I know it won't work but I might as well show it to contribute possible ideas. I would also like to know how good this idea could work, so please criticize

Click for larger view \/

Woops, I sort of made a few mistakes in the Pictures text boxs, sorry
~Lucian

Edited by Lucian, 12 October 2008 - 07:40 PM.

[hereticorp]

Lucian, on Oct 12 2008, 08:33 PM, said:

Since this thread just got bumped I thought it would be fun to spend 15 minutes working on a weight adding system (sp?), I know it won't work but I might as well show it to contribute possible ideas. I would also like to know how good this idea could work, so please criticize

Definitely not practical, we want to keep the blank upright so as not to have to deal with the issue of rotating it.

But thanks for the thought.

roboman, on Oct 12 2008, 07:08 PM, said:

You should use one of these for your control system. I've been using them for a few years now, and they are really easy to program, and have 16 I/O pins. Also, you could use servos as your actuators.

Can't say I've ever seen or used anything like that before, but I'll look into it. Thanks for the suggestion, and I'd appreciate any specifics about where I could learn to program them.

[Icespartan 1114]

That looks and sounds really complex, How long it take you to make it?

[hereticorp]

I've added a counter so that I know exactly how many blanks have gone into the bag, this will make selling blanks a lot less annoying.

Enjoy the new pics and vid on the first post.