How to fill 20000 small plastic bags? - Page 1
Forum section: electronics / general

author: JuKu
author_rank: Frequent Contributor
timestamp: September 10, 2013, 01:06:26 pm
content: It seems I need to produce quite a few DIY kits. The plan: Take a big box of part A's. Take 20 (or how many A's there happens to be in the kit, measuring by weight where sensible), throw those in a bag, close and label the bag. Repeat and end up with a box full of bags of A. Repeat for C, D, E,... Then, take one bag from each box to a kit box, tape close and repeat.How can I make this easy? The size of the job is too small to warrant buying a full automated machine. If I would be doing this constantly, it would make sense to drop 20-30k for such, but for a one-off project, no. But the job is big enough to spend some money for streamlining; each second on each bag is more than a day for the whole project. I' willing to spend a few thousand but not tens of thousands.There has to be something between pure manual and big production machines. I'm thinking of a tool that takes plastic tube on and: Close handle, seals and cuts a bag; open handle, presents an open bag. Or something like that, but I haven't been able to find anything. Any hints?For labeling the bags, I think I have to use laser printed sticker sheets, unless you have better ideas.

author: lgbeno
author_rank: Frequent Contributor
timestamp: September 10, 2013, 01:20:58 pm
content: See how much it costs to have digikey, elecrow or smart-prototyping do it for you and spend your time designing the next great kit instead...

author: krivx
author_rank: Frequent Contributor
timestamp: September 10, 2013, 01:41:17 pm
content: Is there some kind of time constraint you're working against or do you just need this to be cheap? Why not hire someone to do it while you work on something else?

author: Stonent
author_rank: Super Contributor
timestamp: September 10, 2013, 02:27:45 pm
content: Adafruit uses a table full of plastic cups. Put each part in each cup. Have two people working the job. Pour cups in bags when done. At about 100 cups you can finish in a few hours.

author: smashedProton
author_rank: Frequent Contributor
timestamp: September 10, 2013, 02:43:10 pm
content: Hire a high school student.

author: mariush
author_rank: Super Contributor
timestamp: September 10, 2013, 03:11:05 pm
content: Get a small motor, some rubber strip or something... get the motor to move the rubber strip at a constant speed.infrared sensor and emmiter ... detects part and a couple of ms later a piston or something triggers and pushes the part into the bag that's after the sensor. Counter increments. If counter reaches the number of parts, led on top of the piston lights up telling you bag is full.Replace bag, push a button on top of piston which resets counter and starts pushing parts in bag again.Now you can put 30-50-100 of these contraptions on the length of the rubber strip and simply put one part at a time on the strip and when a reasonable number of bags are full, just put a new set of bags and resume placing parts on the strip.blue squares = infrared emitter and sensor , red square on top is the bag, red square on bottom with T is the piston pushing part in bag.With long enough strip you can put about 100-200 parts on the strip and then just get busy replacing bags and resetting the counters

author: sleemanj
author_rank: Super Contributor
timestamp: September 10, 2013, 04:36:40 pm
content: Small resealable (ziplock) bags are quite fiddly to work with, a lot of time would be spent just getting them open, holding them open and trying to pour the stuff in, especially if you use the smallest ones.What if instead you had a sheet of heat sealable plastic, you put this on a grid template, marking out component bag sized areas say 10 by 10, into each space you dump your parts in a pile, then put another sheet of plastic on top.Then take a "sealer" grid you made which presses down over the top and heat seals along the grid lines (nichrome wire and kapton ?) so that you now have formed pouches full of parts, slap a sticker on each one and dump in a box.If you were weighing parts, I think you could really rip through them if that idea worked.

author: envisionelec
author_rank: Frequent Contributor
timestamp: September 10, 2013, 06:49:48 pm
content: Quote from: JuKu on September 10, 2013, 01:06:26 pmBuddy, I've been here.Buy a continuous bag (literally a very long tube of bag material) and a heat sealing/impulse machine. You can hold the bag open using a fixture made from your imagination. I would use an air nozzle to blast it open. It will keep its shape for as long as it takes to throw parts in. You'll have to cut the sealed end off. Buy a rotary blade from a fabric store. Then make a guide to position the blade close to the back of the sealer. Blast a bit of air from under the table to pop the tube up into your hand and drag through the sealer, then continue to the second air-blast to open the tube. You'll spend maybe $200 in valves, nozzles and a used bag sealer (eBay). The tubing can be purchased from Uline. Get a dual footswitch to handle the valves.

author: edavid
author_rank: Super Contributor
timestamp: September 10, 2013, 07:46:21 pm
content: If you can source your parts in China, you should just have it done there. It may even pay if you have to ship some of the parts.

author: johnboxall
author_rank: Unknown
timestamp: September 11, 2013, 07:39:07 am
content: Can you tell us more about the kits?

author: SeanB
author_rank: Super Contributor
timestamp: September 11, 2013, 06:18:42 pm
content: A little overkill will be to look for a used form fill and seal machine, and then just drop the parts into the hopper as needed and press manual step. If you use a lined foil sheet you can get ESD protection bags for free.

author: Corporate666
author_rank: Unknown
timestamp: September 11, 2013, 09:43:27 pm
content: You said each wasted second adds more than a day to the total project time, 29,000 seconds in a day so I am guessing you are doing 30,000 or more of these kits.We put together a lot of accessory bags for stuff we make, and once I get over about 5,000, it definitely makes sense to outsource. You won't be able to beat the costs for automating (whether a little or a lot) yourself unless you are doing hundreds of thousands of kits, IMO.There is also various level of automation. We have these big spinning carousels that go in the center of a round table and have pie slice shaped compartments. It's easy to automatically dispense the parts into each compartment and then into a bag (either automatically or by hand).