Monday, August 22, 2016

Idea For A Mass Producible Wooden Storage Box

I like things to be organised.  Over time, I've found the best way to accomplish this is to store similar things in labelled boxes.  It looks neat and tidy and makes it easy to find exactly what you want when you want it.

The exact form factor of the boxes has so far been an iterative process where I learn the pros and cons of each design as I use it.  I currently use cardboard boxes, but the long term goal was always move to wooden boxes.  I have only a few requirements.  They need to be big enough to hold a sheet of A4 paper (297mm x 210mm), and they need to have a lid to prevent dust covering the items I want to store.

The title of this post mentions the term "Mass Producible".  I should clarify that I mean making about 100 boxes, not millions.  With that in mind, I also want to be able to use automated manufacturing methods like CNC routing and laser cutting to make the parts of the boxes.  It would be great if I could get some furniture grade plywood delivered to a workshop, have them cut the pieces, and all that was left was a bit of assembly.  I haven't been able to find that capability yet, but it'll happen one day.

So what have I come up with?  Nothing too ground breaking.  In the image below you can see that there are standard box joints in the corners.  For this job, box joints are pretty much the only way to go.  Although the image below has been rendered with a plain piece of timber, I actually want to use plywood and making the thickness of the ply as small as practical is important as it reduces the weight of and size of the box.  With thin pieces of ply, nailing or screwing into the ends can cause problems with splitting, the box joint eliminates this as an issue.  It also make assembly easy.  Glue and clamp.

Wooden Box
Storage Box with Sliding Lid

With the lid removed you can see the rebate that allows it to slide in and out.

Wooden Box
Rear View of Box with Lid Removed

With the back and side removed you can now see a couple of extra features.  There are grooves cut into the sides that allow removable dividers to be added and removed as needed.  The shape of the base is now visible as well.  Traditionally you would just cut a rebate all around the bottom for the base.  So why have I gone for the convoluted tabs?  Once again, plywood.  Depending on the depth of any rebate and the direction of the grain in that layer of the ply, there is a risk that when a heavy item is placed in the box, the ply could fail.  This stitches the base and sides together for greater strength.

Wooden Box
Rear view of Box with Back and Side Removed

Of course this creates some problems.  If you're laser cutting the tab holes and they go all the way through, everything is fine, but if they only go half way, they need to be routed and need t-bone fillets added to allow the tabs to be inserted.  This is because you can't cut an internal square corner with a router bit.

Wooden Box
Box with Base Removed

I don't have the capability to manufacture these at the moment.  Ideally I'd start off by routing all the features that don't go all the way through on a 1200mm x 2400mm sheet of plywood.  At this point it's still one sheet that's easy to move.  It would then be laser cut to produce the final pieces.  I don't even know if this is something that's done commonly.  The reason for this is that you need the nice square internal corners that a laser produces for nice box joints.  I might be able to play around with the joints to make it a one step process by routing though.

So what's next?  Like I said, I can't manufacture them they way I want yet.  That doesn't mean I can't play around with the form factor though.  Stay tuned.

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