3D printing is cool, but have you tried 2.5D printing?

20190617 2-5D Print Thin Wall 3D

Over the last 18 months or so I’ve been stripping back FDM 3D printing to its basics, experimenting with a variety of materials, composites and patterns designed to be printed flat and assembled into more complex 3D forms. Why?

Well there are many reasons why you might want to use a 3D printer to create relatively flat forms: firstly, as anyone who has used a 3D printer would know, the process is extremely slow. The less vertical height you need to print the faster your part will be completed (generally). Secondly, most accessible 3D printers have a very small build volume, and often you want to 3D print something huge. By 3D printing a lot of smaller, flat parts and assembling them later, you can create a large 3D printed object on a small machine (for example check out the full length inBloom Dress by XYZ Workshop which was assembled out of 191 smaller panels).

This type of 3D printing has actually been called 2.5D printing, since it is essentially the production of 2D geometry that is extruded in a single direction. No fancy lattice structures or compound curves here! Below are some examples I’ve printed over the years, and while some of them like the mesostructure (centre) may look complex, the geometry can be described by a single 2D drawing and extrusion (Z) dimension.

20190617 2-5D Print Examples

What I’ve learned is that when you are 2.5D printing often thin geometries, optimising the dimensions of the geometry for the specific capabilities of your FDM machine are critical. In fact, just a 0.1mm change in the thickness of a wall can reduce your print time by ~50%, which is a huge time saving. Knowing what these “magic” wall thickness settings are is powerful, and also very simple when you understand the logic.

This information has now been published in a book chapter titled “Designing Thin 2.5D Parts Optimized for Fused Deposition Modeling,” and provides several equations you can use to quickly calculate the optimum dimensions you should use if you want to 2.5D print (or even 3D print) as quickly as possible with maximum accuracy. Below is a visual graph that can be used to select the optimum wall thickness settings when 3D printing with a 0.4mm nozzle, and also shows the effect STL resolution can have. Full details about this graph can be found in the book, however the short version is that you want to be designing thin wall features using dimensions that fall inside the black boxed (or dashed) regions. So, for example if you will be using a 0.8mm printed wall thickness (representing 2×0.4mm extrusions in your slicer), the optimum dimensions to design with in CAD are 0.5-0.8mm, 1.3-1.6mm, or 2.0-2.3mm. Anything outside of these dimensions will require some level of infill structure which takes longer to print, and can result in a more messy part.

20190617 3D Print Thin Wall

For a part similar to the mesostructure earlier, we calculated that simply adding 0.1mm of thickness to the design from 1.2mmm up to 1.3mm would decrease print time by 38% – yes, it sounds counter-intuitive, but adding material can actually reduce print time!

Designing for additive manufacturing (DfAM) is a very important research area, and it is knowledge like this that I hope can be implemented by designers, manufacturers and others involved in 3D printing. If you want to learn more about 2.5D printing, and the equations you can use to calculate the “optimized zones” for your own 3D printer, please check out my chapter which can be purchased with a 40% discount using my author code “IGI40,” or if you are at a university you may find you already have access through your library subscriptions.

Happy 2.5D printing.

– Posted by James Novak

From Sketch to 3D Print

Sketch to 3D Print

Designing your own 3D printable object can be daunting if you’ve never used a 3D CAD program before. This is a challenge that one of my university classes is facing, with most of the students new to 3D design, but eager to begin experimenting with 3D printing. So this week we explored a workflow that allows them to take their hand-drawn sketches through a couple of simple processes, resulting in a 3D printable file, without having to model in 3D from scratch. So here it is just for you – follow along and let me know how you go.

Step 1: The Sketch

biro sketches

This is the easy part! Find a sketch that you’d like to turn 3D. It’s best if it’s drawn clearly in pen, so if your sketches are in pencil just trace over them on a fresh sheet of paper. For this example I’m borrowing a sketch from online. You must then digitise your sketch – best using a flatbed scanner, or take a photo in good lighting conditions so you get good contrast between your linework and paper.

Step 2: Vectorising

Illustrator Tracing

We are going to use Adobe Illustrator to automatically trace the outlines of our sketch. Place your sketch into a new document, and you will see a “Live Trace” or “Image Trace” button appear (depending on your version of Illustrator) near the top menu. You may find that one of the preset options will give you an accurate tracing, or you will need to get into the options and start tweaking the settings. I have an older version of Illustrator, but the settings that work for me are shown above. What you are looking to achieve is a good level of detail, and nice closed lines. Once you have a good result, you can use the “Expand” button to turn the result into individual lines that can be selected. You can also go to the menu and select Object>Ungroup so that your linework is no longer all grouped together as a single item.

Step 3: Exporting

Illustrator SVG

If you have a collection of sketches like this example, you will want to now Save your file (so you can come back to it and make changes later on), and then delete everything from the file that you don’t want to turn 3D. For this example, I have just left the flower tracing that was in the top-right corner. Go to File>Save As and save this drawing as a SVG file. This is a 2D drawing format that will be recognised by our 3D software.

Step 4: Going 3D

For this example we are going to use the freely available 3D software Tinkercad – one of the best features being that it runs from your internet browser, no need to download and install anything. I recommend it as a great place to start your 3D modelling journey, however if you’re already using a more advanced 3D CAD program you can still follow along with this tutorial – the process will be quite similar.

Tinkercad Import SVG

Create a new Tinkercad file, and at the top right of the workspace is the “Import” button – select your SVG file and it will automatically be turned into a 3D object as shown above. Depending on your sketch and requirements, this might be all you need to do and you can jump straight ahead to Step 7: Exporting. However I want to make some modifications to this design now that I have a good starting point in 3D.

Step 5: Modification

Tinkercad Cut

For my needs this object is too thick – I only want it to be 2mm tall. In the right panel of objects is a translucent box – this box is like a cutting tool, anywhere it touches my 3D object it can be used to cut away at it. Place a box in the middle of your 3D model, and use the Length and Width sliders to fully enclose your 3D model. Lastly, rotate your model to a side view and you will see an arrow pointing up or down – click-and-drag on this to move the box up 2mm above the workplane.

Now select both the 3D model and the box (either click-and-drag a selection box around the workplane or hold the Shift button and select both objects) and you will notice at the top right the Group icon becomes available. Click on this and Tinkercad will subtract the box from the 3D model, leaving just a 2mm thick object.

Step 6: Patterning

Tinkercad Pattern Duplicate

Rather than just printing one of this design, I want to create a more complex pattern. Firstly I need to scale the design down so that it’s a bit smaller. Do this by clicking on the object, holding the Shift button and using the corner handles to click-and-drag the object down in size – mine is about 40x40mm.

With my object selected, at the top left of the window are the standard Copy and Paste actions, as well as the Duplicate option – this is the option I use to make copies. It may copy the object in the exact same position as the original, so when you click Duplicate just click-and-drag this copy out into a new position. Repeat as many times as you like to create a pattern.

When you’re happy with the design, you will need to join all of these individual elements together into a single object. Similar to step 5, select all the objects together and the Group button will become active – however because all of these objects are solids, the Group function will join them together rather than cutting away.

Step 7: Exporting

When your design is complete, use the Export function at the top right of the window to download the object to your computer. The STL option is most likely what you will want for 3D printing. The STL format is the standard file type for all 3D printers.

Step 8: 3D Printing

Up Plus 2 Pattern

Finally you can load your STL into your 3D printing or slicing software and 3D print! If the print doesn’t give you the result you want you can either go back to the Tinkercad file and make some more modifications in 3D, or take a step further back to Illustrator and modify the original linework.

The process is not perfect or overly accurate, however for designs like fashion or simple experiments, this can be a good workflow to try if you’re better/faster at drawing by hand than modelling directly in 3D software. If anyone has some different workflows they enjoy using, please feel free to share them in the comments section 🙂

– Posted by James Novak

Turning a 3D Printer into a Plotter

20160304_robot-picasso

My last couple of posts have been about the Robot Picasso Kickstarter I’m currently running, a project that developed after the failure of the Solidoodle Press 3D printer. It’s attracted some media attention from 3dprint.com and Digital Trends who have followed up the saga of Solidoodle, the company going bankrupt because of the failings of this one printer.

Given the success of the Kickstarter, which is over 300% funded with a few days still to go, I thought it was about time to show the special 3D printed part that has converted the 3D printer into a 2D plotter. I developed the part in Solidworks using just a few key measurements, in particular the 2 front screw holes and the distance needed for the tip of the pen to lightly touch the plate where paper would be stuck. It sure beats using rubber bands and sticky tape which is how the initial experiments began! You can check out the 3D model below.

This is something that you could create for any 3D printer since most extruders have some sort of screw holes that you could take advantage of (for example you can see them in my Cocoon Create printer in this previous post), or perhaps you could design a clever snap-fitting system similar to the tutorial I wrote for Formlabs last year which shows the step-by-step process to designing a snap-fit enclosure. As long as you can create a secure fit, you will be able to get consistent results using your 3D printer as a 2D printer (plotter). If you want to see the process of drawing with this attachment, just check out the Kickstarter video I put together showing the full process of Robot Picasso. It’s a fun way to add a whole new function to your existing 3D printer if you can turn a 2D drawing into simple G-code commands.

– Posted by James Novak

A High-Tech Plywood Box?

20150712 IR Box

Following on from my post a few days ago, the gluing of the plywood box is now complete 🙂 I had to take it nice and slow with a couple of the pieces slightly bowed, and as you can see in the third image, I had to use a few small nails along a couple of edges to hold it all in place while the glue dried. A few good clamps also helped do the trick as well, as in the first image.

I’ll admit my 3D modeling wasn’t perfect; I had originally designed the box in Solidworks with a 3mm sheet thickness, but had to change this on the fly to 3.5mm based on the available plywood sheets. Somewhere during this process a few dimensions got thrown out of alignment (obviously my parametric relationships need some work!) so the 2 end pieces needed a couple of the tabs to be slightly trimmed back – nothing a saw and a file couldn’t fix, although my pride might need a bit more work!

If you look closely at the middle image you’ll see some wires coming out of the box – these are infrared sensors that I’m going to have a play with connected to my Arduino. Without giving too much away just yet, I’m planning to use this to play around with some CAD files, using Rhino + Grasshopper + Firefly… the rest I’ll leave to your imagination!

– Posted by James Novak

2D for a Change

2015-06-30 Laser Cut

As a departure from my usual 3D printing talk today’s post is going a little 2D, featuring laser cutting. As part of my PhD research I’ve been playing around with all sorts of sensors, Arduino, Rhino, Grasshopper… and plenty more (you can check out the last post here). One of my latest experiments needs a box to mount some sensors inside, so forming a custom box with mounting holes seemed a great excuse to think a little 2D for a change.

The pieces were designed in Solidworks, and only 2 unique pieces were really required – the main length and the end piece. These were just copied and tweaked to form the slight variations. There’s something nice about the concept of combining the natural timber with some high-tech sensors, so 3.5mm plywood was chosen as the best material. The dimensions I used were to make optimum use of the sheet size with minimum waste, as you can see in the first image. Overall the cutting of all pieces wouldn’t have taken more than 10 minutes, and while the laser didn’t always cut completely through the sheets, it was nothing a bit of brute force and a file couldn’t fix. There’s also a slight bow in a couple of the pieces, so gluing them to form the box might be a little tricky – I’m hoping a few small nails might do the trick without splitting the laminated veneers apart. I’ll add some photos of the final result when it’s complete.

– Posted by James Novak