Make Card Prototypes Fast - With The 3D-Printable "Card Rabbet Tool".

WHY PROTOTYPE IN CARD & WHY THIS TOOL HELPS:

If you work in Product or Industrial Design, you'll have almost certainly made a load of mock-up or proof-of-concept models from Cardboard, Plastic, Foam of other cheap materials, before progressing to CAD... I have a particular interest in simple modelling techniques like this - and started a website called Design Modelling, dedicated to this. I demonstrate methods to work with Cardboard to create a robust and aesthetic joint - called a "Rabbet Joint" in the US, and a "Rebate Joint" in the UK. This is done by filleting-out a the edge of the card, so that the other piece can glue in securely. Take a look at examples made using these techniques, like:

If you are familiar with these techniques from my website, then this tool is going to make life so much easier!

UPDATE: If you don't have a 3D printer - you can order this from Shapeways, here.

If you want to know more about the early stages of Prototyping in Sheet Plastic, there is an Appendix at the end of this Instructables giving more detail.

In reference to the images above - if you are interested in knowing more about Cardboard Modelling Techniques and how companies like Dyson, NASA and Raspberry Pi have explored and utilised this, may also enjoy a talk I gave at IDEO, London on this subject.

Please note, the DC07 Card Model image is a public image and was not made by me, but was the sort of thing I got up to while working at Dyson.

And finally, I think there is a good mix of 'teaching' in this I'ble - not only of new skills, but also pushing the ideas of making your own tools from scratch, so if you enjoyed this, please vote. Thank you.

Step 1: Set-Up: TECH // TOOLS // EQUIPMENT // CAD FILES

TECH

- [DOWNLOAD CAD FILES FROM DESIGN MODELLING HERE]. I've included both .sldprt (for editing) and .stl files (for printing, with no edits).

- 3D Printer. You may have your own (I use an UP! Plus), but check this guide from Make: out if you are new to it.

- Material to print in. I started with ABS, but you can use other materials such as PLA; read up on these materials here.

TOOLS & EQUIPMENT

- Pliers (for pushing in nuts to print, friction fit)

- Screwdriver

- SuperGlue (please use goggles)

- Swann & Morton No.10 Scalpel Blades (x2)

- 1 Stapel (yup, a typical stationary staple)

- M2 Nut & M2x8mm Bolt.*

- N35-N42 Neodymium Magnet - 4mm(l) x 4mm(diameter)* [e.g.]

*Being European, I made this in Metric. So you have these options in the US:

1. Easy: Use the next nearest size to an M2, (1/64), which you'll find here.

2. Up for a challenge: Change the CAD yourself, using the .sldprt files, or modifying the .stl files if you prefer...

Note - the main objective is that your bolt can pass through the No.10 Blade 'socket', and that any magnet you choose holds the blade securely.

Step 2: Notes on CAD, Editing and Printing...

You can skip this if you just want to print and have all the parts listed and are ready to go.

TIPS ON CAD & EDITING:

If you want to modify the CAD - this was modelled in SolidWorks (yes, a legit copy). The video give a preview of the mode and how it was assembled. I confess, been a little bit 'amateur' in that I've modelled the two parts in one file and then simply hidden the other, but I thought this would give some useful insight into editing, and if you are less experienced, it'll be easier to work with, and if you are Pro, you shouldn't sweat it - just forgive my Cowboy-CAD!

Truth be told, even when working on professional projects, one often remodels very complex CAD again from scratch, as it's will have accumulated inefficiencies as the design evolves. There is a balance between when to be fast/creative (justification of Designers), and when to be flawless when tooling (understandable need of Engineers). You decide what standard you need you CAD to be... perhaps check out the excellent CAD Junkie for tips.

TIP: You'll see that I've included the CAD for the No.10 Blade, and I modelled this myself as it did not appear to be on GrabCAD or the like. I thought I'd show this for those interested in CAD and also those who might want to try out different blades, so this is a great video on how to work from a sketch/image and get it into CAD.

TIPS ON PRINTING:

I printed this on an UP! Plus 3D Printer. I used ABS, with a resolution of 0.15mm/layer, printed on 'Normal' quality. I think it requires 8g of ABS, so about 35p in materials. It took about 40mins.
The 'slicer' by UP! seems to be especially good and well reviewed, but I'm not sure how your's will build on a different machine, so check out the reviews.

However, the key thing to appreciate is that building it 'flat' for me took more material (as it made a larger 'raft'), hence I made it (as shown) - 'upright'. It also means that things like the delicate holes for the bolts are build in profile, rather than in layers. This might be obvious/debatable for you reading this, but I hope it's useful either way. Again, some great articles on Make: for this sort of detail, if you are curious.

Anyway - back to the main project...

Step 3: Assembly 1: Fix Magnet to Horizontal Blade

Now that you are all set, 3D Prints cleaned up, you are ready to roll:

1. Align your No.10 Blade in the location underneath.

2. Check fit. Hold in place and flip over...

3. (still holding blade in place), ready with magnet. Insert into hole.

4. Press magnet down - until you hear it 'click' into place - flush with the magnet. If it is a tight fit, this is ok, but be sure it does not push too far, so as to push the blade from being flush with the plastic.

5. Tack with SuperGlue (then add more when confident it is in place).

6. When happy SuperGlue has taken hold, remove blade and clean away any excess glue.

Step 4: Assembly 2: Fix Retaining Stapel

As you can imagine, it's very small thickness to cut just above the lower piece of corrugated card, and as such a general household/office staple was the perfect thing to hold the blade in place while giving the right offset for cutting.

1. Ready the holes (by cleaning out any support materials, but using a 0.5mm drill bit - or even a spare staple.

2. Fit staple legs into holes and maintain a good pressure, ready for gluing.

3. Apply glue with care - use a nozzle if you have it, if not, put some glue on a bit of scrap paper and 'feel' it into the hole with another spare staple....this is a good trick for other precision applications of SuperGlue.

4. When set, pull away Blade and add a little more if needed.

Step 5: Assembly 3: Press-Fit Bolts

You may need to adjust the CAD if your nuts are different size to the ones in the CAD, but if you do, make sure they are a tight fit. This will allow the nuts to stay in place and not fall out when changing the blade.

1. Load nut in socket.

2. Carefully align.

3. Press nut into 3D Printed Plastic. You may also use a small hammer if you have it too, but with care.

Step 6: Assembly 4: Fit Vertical Blade

1. Ready No.10 Blade.

2. Fit into recess. Ready Part B.

3. Fit Part B over Part A, and pass bolt through.

4. Pass second bolt through (ideally in this sequence), ensuring it passes through the Blade, and tighten.

5. Adjust the 'pitch' of the blade if need with the screwdriver (for safety), and re-tighten fully.

Step 7: FINISHED - Go Make Models & Prototypes!

So now you have created your Rabbet/Rebate tool, you can use it on Corrugated Cardboard (as well as other materials such as FoamCore, Styrofoam and Correx).

If you are interested in making models like this, please check out the Design Modelling website for more projects and tips, in both blogs and video tutorials. Ideal for Design Students and other Creative Professionals.

If you are interested in the Behind-The-Scenes of how this project was first prototyped using Plastic ABS Sheet (before working in CAD) check out the the following Appendices...

Thanks for reading. Let me know how you get on!

Jude

Step 8: Appendix 1: How to Prototype in Sheet Plastic (As Easy As Score 'n' Snap)

The first (of 5) video tutorials on working with sheet plastic, shows how to use this Score 'n' Snap technique - ideal to make quick models from the following exploration for this tool. I used it to understand the following;

How to cut the Vertical part of the card (i.e. through the corrugations)...
How to cut the Horizontal part of the cardboard (i.e. under the corrugations - removing the fillet of card)?

Exploratory Models:

1. I first tried to 'push' through the card, but this seemed too dangerous.

2. I went for a dragging motion. This worked better and was also safer.

3. I then looked at the under-cut (Horizontal) and tried to use the card as an offset - but this was too thick/high.

4. ...so I used the card itself to act as the appropriate offset. It worked fine.

Happy with these models, I needed to combine them in one model. Time for CAD...

Step 9: Appendix 2: Refining CAD Models

Moving into CAD (SolidWorks), I created the following models:

1. A 'block' model, taking no more than 10mins to make, but allowed me to print it and check the dimensions that I had deduced from the 'sketch models' in plastic sheet, earlier.

2. A more minimal, ergonomic model - rounding parts out. Note, this is still one part and the blades are glued-in.

3. A functional model - making the 'clamp' for the blades, allowing them to be changed once blunt.

4. Although each time refining the blade position, this final model was the 'cost-down', where I realised I could do without one of the magnets.

5. Showing the staple, which luckily anchored the blade, while giving the right offset to cut the card.

So next I trialled it on different materials...

Step 10: Appendix 3: Update - This Works on Other Materials!

So although I designed this originally for Corrugated Cardboard, I also found it worked great on:

- FoamCore (used a lot by architects)

- Styrofoam (used a lot by modellers and sculptors)

- Correx (other than billboards and signs, I'm not sure who uses this in Design, but I used it on a project to put a Capsule into Space... so you never know when this might come in handy!).

Anyway, please let me know if you come up with any cool variations where this tool works well, or even create your own tool using these techniques. Follow Design Modelling on YouTube and Twitter for updates.

Cheers,

Jude