Cardboard Engineering is a quick way to try out different configurations in reality. As the name says, this is done using cardboard. However, there are a few alternatives. Let me show you a portfolio of different ways to make cardboard models with (not only) cardboard, from ultra-cheap to very fancy. Please note that the fancier methods are usually not so well suited for layout optimization, but more for workstation optimization.
If you are doing a layout workshop, a very cheap and quick alternative is to mark on the floor using chalk. Normal blackboard chalk is too brittle here, but for very little money you can get sidewalk chalk (or you borrow it from your kids).
Rather than building a cardboard model, you simply draw the future layout directly on the shop floor. This is a quick and easy way to visualize the future shop floor layout. Use different colors, and label the items. Also, for obvious reasons do not use it in a clean room or generally on clean floors! In this case painters tape maybe an alternative.
A very cheap and readily available material is lumber, boards, and other wood products that can be assembled into different shapes. The images here are courtesy of Hermann Ultraschall. This material is readily available in pretty much all hardware stores, and it is likely that at least some of your team has some experience assembling wood. Hence, it permits you to create quick mock-ups of your workstations.
Of course, you need some more tools like a wood saw (hand or electric) and a screwdriver with bits and screws (and I heavily recommend a cordless one over non-cordless or even manual screwdrivers). For corner connectors you can either improvise with screws or also get some cheap wood connectors made out of perforated sheet metal. It is also possible to use a nail gun, but please be aware that nail guns are a major accident hot spot, especially for people who use one only occasionally.
ASSTEC Cardboard Engineering Kits
You can also buy quite nice pre-prepared cardboard items designed especially for cardboard engineering. I got a free sample of such a product from ASSTEC in Germany. Their kits consist of 45x45mm rigid cardboard tubes, corner connectors, plugs, and flat cardboard plates. The photo here shows a cardboard robot that was presented by ASM at the Lean Conference in Frankfurt 2018. On the ASSTEC website you can see photos of much larger installations. The result is actually quite sturdy. On one of their images I saw a young lady sitting on such a structure – although this lady probably weighs significantly less than me.
The photo below shows the details of these black plugs in open and closed positions, both on their own and from the inside of a tube. These plugs can be reused for the next project.
The photo here shows the unassembled and assembled corner pieces. These cardboard pieces are pre-cut and notched for easy folding and assembly. You need a drill with a wood drill bit to drill the holes into the cardboard tubes. You also need a wood saw to cut the profiles to size. The flat cardboard sheets were also notched to make folding easier. As the robot above shows, you can also make movable joint connections.
The end result looks quite impressive, and has the potential to impress your boss and your customers. They are almost too nice to throw out. It does take a little bit longer to build, and it requires also a bit more engineering skills, as you have to measure and cut to size, whereas with normal cardboard you often just “wing it.” However, it looks much nicer. Below is their product demonstration video.
Plastic Tubes, Aluminum Profiles
The hardware store also sells other options for a quick mock-up. For example, you can buy cheap aluminum profiles with corner connectors to also create a mock-up quickly. Price-wise they are comparable to the cardboard profiles. They do require a bit more engineering thought for the lengths of the profiles to match, and sawing and drilling them is also a bit more difficult than the cardboard profiles from above. Another flaw is that they may look too permanent. You have to consider the reaction of management and workers to a permanent looking mock-up. It may be not a problem, or it may raise eyebrows about the perceived cost.
Similarly, there are also systems using inexpensive tubes and matching connectors. These are also sturdy enough for permanent structures, and fall somewhere between a mock-up and a permanent installation. The image on the left shows a permanent testing station from Suzuki in Hamamatsu, Japan.
The gold-standard for permanent construction is of course dedicated aluminum profiles. One common maker is for example Bosch Rexroth. The image on the right is from the Bosch section in Arena 2036. However, since these special profiles cost three times as much as a simple aluminum or cardboard tube, it would be an expensive mock-up. It is best used for permanent designs – and of course you can make a similar workshop to directly create a final design rather than creating mock-ups. These profiles are widely used in Europe, but Japanese companies often go for cheaper round profiles.
A new concept I recently came across is a Lego-like structure. You probably know LEGO toys, and can imagine that building a real-life structure from LEGO bricks is cumbersome. Even the next size up DUPLO would require still too many blocks. However, EverBlock makes LEGO-style blocks in 12x6x6 inches (roughly 30x15x15 cm).
While I haven’t tried it myself yet, these blocks are designed for assembly of usable structures. Their portfolio pictures show desks, counters, room dividers, and many other examples. Hence I imagine they can also be used to create engineering mock-ups – which are also sturdy enough to be used. The system also includes flat surfaces and shelves. The blocks also have through holes that can be used for electric wiring or stability enhancing dowels. If necessary they can also be drilled or screwed into. Construction is – literally – child’s play and very easy. After use they can also easily be disassembled. Long-term use may depend on your workshop environment, and I would not use this for example in a welding shop. But then, I wouldn’t really use cardboard either.
A single 2×4 block costs around $7, or $5 for recycled plastic if color is not that important to you. A comparable structure made from EverBlocks is by my estimation probably a tad more expensive than the cheap cardboard or aluminum profiles, but cheaper than a Rexroth profile construction. You may need a few blocks for larger projects, but they sell anything from single blocks to 8,000-block truckloads.
Computer, CAD, and Virtual Reality
Finally, there is the option of computer and virtual reality. You can create and change models in CAD – although this requires people skilled in the use of your program. Another option I tried out recently (and on which I will write a bit more soon) is a virtual-reality tool for shop floor design reviews by R3DT. Their product creates a virtual 3D environment using VR glasses like Oculus Rift and HTC Vive. Merely by moving your hands without any controllers you can experience, interact, and modify a virtual shop floor.
All modifications with computer models have the drawback of requiring a computer model, which may take a lot of time up-front. However, in many cases such a model already exists, which makes it a lot easier.
Which One to Use?
Which one you should use depends on your situation. If you have lots of lumber lying around anyway and your people know how to handle it, use lumber. If it should look extra nice, use Asstec cardboard profiles or aluminum profiles from the home depot. If your people feel comfortable with computers, you may use CAD or a virtual reality environment. And don’t forget that you can combine these approaches. Make the frame from lumber, and use cardboard for the gadgets attached to the frame. Take whatever feels best for you.
Regarding cost, below is a rough estimate of the cost for a single 2m-long profile or a similar equivalent to give you an idea of the magnitude of the cost. This does not include any connectors or joints. For EverBlock I did an estimate for a 60×90 wall vs. a similar wall made from other materials to place it roughly on this chart. Of course, for all these there may be volume discounts or bulk orders possible. The CAD and Virtual Reality model is not on the chart, since you usually pay per seat, and the cost per model depends on how much you use it.
Overall, there are many different alternatives to cardboard engineering, and most of them can be combined. Hopefully this includes something that you like and can use for your work. Now, go out, cut up some cardboard, or lumber, or aluminum profiles, or fire up the computer, and organize your industry!