When I started my residency at Pier 9 just over a month ago, I wanted to quickly test out some of the machines I had recently received training on. One of those was the Metabeam Laser – a 400 watt laser with a 4’x4’ bed –a great prototyping machine! I didn’t want to spend a lot of time on these tests, so I decided to make a smaller version of a large commissioned lamp I made a few years back. Since the original design was parametric, I was able to change the parameters fairly easily to resize the lamp and modify the overall form. In the original Grasshopper definition, I had built in automatic part layout and labeling. However, as is common with GH definitions, some of the components were outdated and so this part of the definition was essentially broken. Rather than re-build and fix it all (it was fairly large) I decided to try 123D Make and see if it could work for what I wanted.
To see the process from start to finish read on, but first here are the things I used to make this lamp:
-Rhino 5 and Grasshopper -123D Make -some sort of rigid sheet good (I used ⅛” white acrylic) -access to a laser cutter or other 2D CNC cutting tool (i.e. a waterjet) -glue or solvent
Step 1: Prepare Your Model for Export...
I tested various ways of exporting the form I created within Rhino and eventually found that the best way (for me) was to thicken the surface into a solid in Rhino first. 123D Make has a shell/thicken option, but the offset surface as a solid in Rhino worked better for my needs. I also found that I preferred to rotate my model in Rhino from the Z+ axis into the Y- axis so that the .obj came into 123D Make with the ‘top’ of my model oriented the way I wanted. Next you will want to export your model as an .OBJ file. This will mesh the object, so choose an appropriate mesh resolution for the level of detail on your model.
Step 2: Import and Adjust
Open 123D Make and import your file. One of the first things you can do is to choose a construction technique. I was basically trying to recreate a radial slicing technique I developed in Grasshopper, so that’s what I went with. Depending on your model you may have to move and adjust the slicing axes. You do this by clicking on ‘Slice Direction’ and manually adjusting these options. If that is to your liking then go ahead and click ‘Slice Distribution’.
Step 3: Slice It Up!
The default slicing in 123D is 10 slices radially and 10 in the vertical axis. I only wanted 2 in the Z or vertical axis and I wanted as many as I could radially. I played with adjusting the number until I got a density that looked good - for this particular model 60 radial slices was about as many as could fit without colliding. The default placement of the 2 slices in the Z axis wasn’t ideal, but that wasn’t a problem - you can use your cursor to highlight a slice in the model, then click it - you can then drag a piece to the desired location. You have to do this visually as I don’t believe there is any numerical input available, but you can still get pretty close if you have a good view angle!
Step 4: Sheet Setup/Manufacturing Settings
Once you have your model sliced in a way that works, open Manufacturing Settings and create a new material - give it a sheet size and thickness and a slot offset (for fitting / tolerance) The fitting and tolerance is important as it can be the difference between your parts fitting together well or not at all. I ran some cut tests prior to cutting the job to verify the tolerance. In the end the fit was a bit looser than I wanted, but this was better than being too tight! The sheet size is not all that important unless you plan on cutting straight from the .DXF files produced with 123D Make. I recommend cleaning them up in another CAD program first. I used Rhino to move the cut files into a more efficient layout than was produced by 123D Make. You could also use AutoCAD or even Adobe Illustrator. Since I essentially did the layout manually, I wanted the all the pieces on a single sheet layout so I gave the sheet a 96” length x 48” width. This fit all the pieces no problem and created only one file when I exported the .DXF
Step 5: Edit Your .DXF As Needed
After exporting your .DXF , open it up in your CAD program of choice and organise the pieces, make adjustments etc. I was able to manually nest all 60 rib profiles and the 2 rings on (2) 24”x36” sheets. I put all the pieces in a sequential order. For some reason 123D puts the ribs in no apparent order. The pieces are numbered, but this doesn’t necessarily make it any easier as the pieces nest in a sequential way. I also offset and trimmed the rings to my liking (so the outer edge wasn’t flush with the ribs) and added in some features (for suspending the lampshade with a universal fixture I had previously designed and made) Depending on the machine you intent to cut with, most likely now is a good time to name and order your layers for cutting - engraving, followed by small holes, followed by outer profiles and so on.
Step 6: Cut Your Parts
I’m not going to go into too much detail about this step as it’s really dependent on the machine you’re cutting on. As mentioned earlier, I cut these parts on the 400 Watt Metabeam here at Pier 9. It made short work of all 62 pieces, finishing each 24”x36” sheet in under 10 minutes (most of the time was in the tedious engraving of the labels!) When you remove the pieces from the laser take care to keep them in order (especially if you’ve taken the time to lay to order and nest them in CAD!). I try to stack them sequentially in manageable groups. This makes keeping track and assembly much easier!
Step 7: Assemble the Pieces
Since I cut my pieces out of white acrylic, it had paper/plastic film on both sides - leave this on while cutting - it keeps the pieces from getting black and smoky. It is a bit of a pain to remove - especially from both sides of 62 thin pieces! Take care when removing the protective film as it’s easy to break a fragile piece! As an optional step, now it the time to finish or treat the pieces in any way you want prior to assembly as afterwards would be too difficult. I wasn’t too keen on the glossiness of the acrylic, so I used a random orbit sander with a 150 grit pad to give both sides a nice matte finish.
Now it’s time to assemble. There are a few ways to assemble your pieces depending on the shape/form and the fit of the pieces. I’ve assembled a few large lamps like this before and found it easier to assemble while they’re suspended - first hang a ring from the center with a few ribs, add solvent, add a few more ribs, repeat…..when you’re hanging the piece to assemble, especially a balanced form such as this, it helps to add the pieces in thirds - for example, begin with pieces #1, #21, and #41 (or #20, #40, and #60) and then add the next one in each sequence, adding solvent to the joints after each turn. This keeps the lamp balanced as you assemble it. This was especially true for this particular lamp since the fit was on the loose side - going from 1-60 in order just wasn’t stable! You might try a bit of a dry-fit first before fully committing to full assembly. Patience is key in projects which have lots of smaller pieces forming a whole. It can seem tedious or like it might not even come together properly at first, but once you get a critical mass of pieces assembled the form will begin to emerge and you’ll be enjoying the process!
Lastly is to hang the lamp on a fixture. For this particular lamp I used a universal bracket I designed for other lamps - it uses a 3 point contact (⅛” dowels through matching holes in the lampshade top ring) to hold the shade in place. This is the last step, but obviously you should think about the method of hanging/attachment early on in your design process!