Need help designing a dumpling machine

[SimpleMech]

As a fun project, I'm trying to design a mechanical machine as simple and elegant as possible to "crease up" a round flat piece of dough around a meatball.

Any suggestions how this could work? If you know a better place where I should ask for help, please tell me.

P.S. You will notice that in the "Top after" image the dough has not come all the way together, I in fact would like it to come together and close.

I've attached an image

 

[pantaz]

First thing that I envision is something like the disappearing handkerchief magic trick -- place it over hole, push down on the center, causing the dough to fold up, then crimp it closed, perhaps with something resembling a camera lens iris.

 

[sardonicus]

Neat, Are you a chef? What's the difference between a dumpling and a potsticker? I've not seen that type in the frozen food aisle but have seen the potstickers, almost the same just folded over like a taco and then crimped.

Ditto on pantaz: a sphincter type machine (but don't put that on the label) hah! S

 

[Danger]

Cool idea, Pantaz.
The only stumbling block that I can think of is ensuring that the meatball actually depresses the dough into the mould cavity rather than just poke a hole through it. Maybe a vacuum port in the bottom of the mould to suck the dough in first... naw, that wouldn't be any better. Hmmm... Rats! I really like the elegance of your solution, but I'm just not sure that the dough would have enough structural integrity to withstand the process. Again, hmmm... a substrate that supports the dough as it's being moulded? I'll keep thinking on it.
Meanwhile, another possible approach is to join two pre-moulded half shells with the meatball in the centre (sort of like a Tootsie-Pop). That presents its own difficulties, of course.
This could be fun!

 

[pantaz]

Cool idea, Pantaz.
The only stumbling block that I can think of is ensuring that the meatball actually depresses the dough into the mould cavity rather than just poke a hole through it.

Good point... hmm...

How about molding the dough into a pouch shape prior to depositing the meatball?

 

[nucleargirl]

What's the difference between a dumpling and a potsticker? S

dumplings are usually boiled in hot water or steamed, potstickers are usually grilled in a pan - and it 'sticks' to the bottom of the pan and get all crispy :) but essentially before cooking, they are the same thing.

the picture looks more like a shaomai - steamed, half-closed dumpling in a round shape usually eaten for dimsum. Dumplings are more a oval shape.

hm, making a machine to do this might be difficult... what you could do is to put the meatball on a stick, and then drape a flexible pastry on top of it - like a tablecloth, and then crimp the bottom of the pastry, before turning the whole thing the right way round and removing the stick...? if that is understandable at all...

 

[Danger]

Nucleargirl, yours sounds like the best idea yet. I wonder if it might be even further simplified by spinning the ball-on-a-stick in a pool of a more liquid batter.

 

[SimpleMech]

Thanks everyone for good ideas and trying to help. I'm attaching a picture of what the end product should look like, please note that the end product in the picture is hand rolled.

 

[Danger]

Okay, then. If that's exactly what you want them to look like, I think that your best bet would be to pre-mould the pockets, drop in the meatball, and then use a multi-point gripper to crimp the top. Pantaz's idea of an iris diaphragm for that purpose would have the advantage of automatically imparting that little twist. (At least, I believe so based upon watching irises in operation. The innermost points of the leaves seem to move laterally a bit as they close.)

 

[SimpleMech]

Danger, I have a feeling that solution may not work. Here's a video of how it's done by hand:

http://www.youtube.com/watch?v=gpSkn6pztNE&feature=related

 

[DaveC426913]

Question: how automated do you want? How many steps / how much time do you want to cut out?

At one end of the spectrum, you might still be laying dough, inserting a meatball, picking it up and closing it, with the only automated part being a faster way to crimp the top.

At the other end of the spectrum, you might want a device that does most of the above steps with little of your involvement.

 

[DaveC426913]

I just watched the video. I was afraid of that. The top is not crimped in one step (like closing a garbage bag). I think that sequential crimping will turn out to be critical - a step you cannot get around.

Doing it in multiple steps ensures that the individual crimps are all even. If you did it in one step, you'd get some creases much larger and longer than others - not out of sloppiness, but because you can't force the even distribution of the folding.

Try doing this with a piece of paper (which doesn't stretch well) and you'll see the problem. Paper just will not behave this way - and neither will the dough unless you do the steps discretely, allowing the dough to stretch just a small bit with each crease.

 

[Danger]

Bloody 'ell! That's a wretched amount of work.
My immediate thought upon watching the video was that your machine would pretty much have to be a couple of robotic hands. Clearly, that is impractical.
I'm certain that there is a way to do it, but I'm not sure what it is. I'm going to do what I always do when designing something: toss in every single thing that crosses my mind and sort it out later.
dough on turntable; vertical plunger to push dough up; curved horizontal plunger to tuck previously lifted dough in behind newly lifted section and hold it in place; perpendicular horizontal plunger to press newly lifted dough into previous piece; withdraw horizontal plunger and rotate turntable one increment
I'll just continue to post thoughts as they occur to me. If any of them are really stupid, please point it out to me so I'll quit thinking about them.

 

[DaveC426913]

dough on turntable; vertical plunger to push dough up; curved horizontal plunger to tuck previously lifted dough in behind newly lifted section and hold it in place; perpendicular horizontal plunger to press newly lifted dough into previous piece; withdraw horizontal plunger and rotate turntable one increment

Let's concentrate on the crux of the process: the actual crimping. Let's assume for now that all setup and placement of dough, meatball and crimping machine is handled manually.

 

[DaveC426913]

Here's how I'm envisioning the core of the device. (see diagram).

Two prongs, one on either side of the vertical edge of the dough. One or both prongs rotate, taffy-puller-style. then they lift up, the turntable moves one increment, and they come back down, repeating the process.

 

[Danger]

Dave, in both your design and my idea about the plungers, we have the potential of the prongs or plungers binding in the dough and tearing it. I don't know if even a Teflon coating can eliminate that.

 

[Danger]

Okay, how about...
Premould the pocket with pre-crimped folds in place. Flash-freeze to maintain shape. Insert meatball. Flash-thaw and crimp the top with pinchers. Still just thinking out loud here.

 

[SimpleMech]

Okay, how about...
Premould the pocket with pre-crimped folds in place. Flash-freeze to maintain shape. Insert meatball. Flash-thaw and crimp the top with pinchers. Still just thinking out loud here.

What's "flash-freeze' and "flash-thaw' ?

I'm thinking about some device that looks like an open palm, when if closes it kind of crimps the dough and contents in it... but not sure if this is a realistic approach...

 

[Danger]

What's "flash-freeze' and "flash-thaw' ?

I'm not sure of what techniques are actually used in food processing. My thought is along the line of blasting the freshly-moulded dough with something like liquid nitrogen or CO₂ to freeze it, and then microwaving or something to rapidly thaw it.
As for your "palm" idea, it seems that it would present the same problems as the other things that we mentioned. The intricacy of the crimps will be difficult to achieve without damaging the dough. The reason that I suggested freezing was to eliminate tearing as the dough is removed from the pre-crimping mould.

 

[SimpleMech]

I fear that freezing/thawing may even complicate thing further. Not sure if such thing is done in food processing at all.

I do appreciate all your effort trying to help me though, I really do.

 

[Danger]

No problem. As I said, I'm just brainstorming. I'll keep thinking on it.