DIY cardboard compactor.

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  #1  
Old 01-02-16, 01:43 PM
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DIY cardboard compactor.

I process a lot of cardboard boxes at home. We buy a ton through Amazon. I've been dreaming of making my own cardboard compactor to make my life a little easier on the space and processing end of things.

My main constraint on this project is cost. I am willing to spend $200 - $300. I figured I need a total of 2000 lbs of force and a 24"-36" of travel for the compactor plate. The safety of the device will be worked out after the main design of the project is completed.

I think my best bet is to use an electric motor and some acme rods. My problem is working out the physics to determine how large of a motor I would need to get the level of force I desire.

Your input is greatly appreciated.
 
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  #2  
Old 01-02-16, 02:11 PM
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Knocking down the boxes isn't enough? What would you do with compacted cardboard after the fact. Harbor Freight has a manual log splitter that may be modified to work in your applications. I think it is less that $100, but would provide you some no frills hydraulics to test your theory.
 
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Old 01-02-16, 02:17 PM
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I don't knock them down.

I don't think the log splitter will give me enough travel.
 
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Old 01-02-16, 04:03 PM
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You would need to start with knowing how much force is needed (in Lb/sq in for example) to achieve the desired degree of compaction. You could probably glean this by looking at specs for commercial compactors. Once you know that, it's not hard to calculate the power required, making some assumptions for the mechanics.

I took a quick look at a compact baler....it has a platen of about 2x3 feet, exerts 4 tons of force, and cycles in 33 seconds. Didn't list the stroke, but it looked to be 2-3 feet. It's power requirements are 120 volt 15 amps.....so you're talking about 1.5-2 horsepower. You want bigger, or more stroke, or faster...power requirements go up proportionally.

Now that unit is hydraulic...gears and belts and threaded rods have more loss.
 
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Old 01-02-16, 04:10 PM
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I certainly don't need 4 tons of compaction. One ton should be more than sufficient.
 
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Old 01-02-16, 04:17 PM
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Having spent the better part of my youth working in a supermarket the compactor did not really save all that much over knocking down the boxes. In a typical bale of cardboard - 4' high x 4' deep x 6' wide - maybe when it was full, you got 6 to 8 inches of compression. How much was due to air pockets from uncompressed full boxes is unknown. However, my memory doesn't include the actual cardboard air channels being crushed to make the bale. Ahhh, memories.
 
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Old 01-02-16, 04:29 PM
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4 tons on that size platen is not all that much. 4 tons over 2x3 feet is only about 9 lbs/sq in. That's just about what your average male person exerts on the ground with his feet when standing still.

czizzi's idea about the log splitter is a good one. You could rig up a ram with some kind of spacers so you could do a stroke, retract the ram, insert a spacer, and then do another stroke. It would take a little longer, but not much.
 
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Old 01-03-16, 12:30 AM
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I think a compactor mainly spares the labor of breaking down, flattening and stacking the cardboard. To take it to the next step by crushing the corrugation I think you are going to need more force. As already mentioned even a ton spread out over hundreds of square inches isn't that much force.

One thing I might consider is a pair of motorized rollers spaced closely together. You flatten the boxes then feed them through the rollers to crush the corrugations and make them a bit thinner for storage.
 
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Old 01-03-16, 02:18 AM
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One thing I might consider is a pair of motorized rollers spaced closely together. You flatten the boxes then feed them through the rollers to crush the corrugations and make them a bit thinner for storage.
Like an old fashioned wringing device on a washing machine from the early 20th century. I still remember the old unit in my grandmothers basement. Didn't Good Housekeeping or Underwriters Laboratory (UL) outlaw them as they were considered bone crushers if people got their fingers stuck in them.
 
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Old 01-03-16, 03:16 AM
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Although your project is doable I don't think your budget would come close to what it would cost to build.
I occasionally have to assemble medical devices and a sharp box cutter and a few minutes is all it takes to break down the mountain of boxes it all comes in.

Although a bit smaller that what you asked about a used residential compactor already has the parts you need and might be able to be modified or used as is.

 
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Old 01-03-16, 05:11 AM
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Here's an idea that you might want to consider. I just received as a gift a Rockwell Jawhorse. By the looks of it that may be what you want. You can build a "container" that could mount on it when crushing boxes. Just a thought. Then the tool can be used for many other things also.

Now here is the interesting part. We at work crush all boxes and never break them down. Too much time wasted. How will you contain the crushed boxes? They can be heavy and cumbersome. Just how much do you need to crush on a given week or month?

Our industrial sized unit requires six bands of wire to holds the crushed boxes together.
 
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Old 01-03-16, 05:49 AM
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I do not flatten my boxes. I want to take a fully formed box and compact it. I'm not trying to make a block of MDF out of my boxes.

To get the 2,000 lb force requirement, I took the maximum size box I would like to be able to crush and used the strength rating of the cardboard printed on the bottom.
 
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