In this IBLE I'll be demonstrating the design and construction of an Automotive Switch Panel.
I was planning on doing this for a long time in order to replace the existing switch panel on my 1923 Model T Street Rod as it was put together as an interim arrangement.
The design went through a few iterations before I felt confident that I could print it out on my 3D printer.
Okay. On to the problem statements.
Step 1: The Problem Statement(s)
Let's start with the drivers' view of the steering column on my 1923 Model T Street Rod.
The rectangular switch panel made from a spare Radio Shack projects box was put together in a couple of hours.
This was an interim measure I had to take at the time to make the car ready for the road.
So, what's my problem with this arrangement? Subsequent pictures illustrate them better than I describe them here below:
- First, the box looks somewhat like a square peg in a round hole - everything around it has a circular theme, and the box stands out like a sore thumb!
- Second, we have the straight edge of the box trying to stay tightly fit around the tubular steering column - this isn't practical and each time my foot hit the box, it moved out of position
- Third, the box isn't deep enough to accommodate the full height of the switches and their crimped connectors, and I had to cut out the bottom of the switch box to make way for the wires - which is ridiculous!
- Finally, there wasn't anything that was readily available off the shelf to warmly hug my steering column
When I first bought my 3D printer, I wasn't ready to tackle a project of this size and complexity because I was just getting started with 3D printing and needed to brush up on long lost skills - such as 3D modelling.
Now that I've tuned my skills a little bit, it was high time that this idea took physical form.
Step 2: Setting Up Shop.
This arrangement is typical of what a desktop 3D printing hobbyist would already have (or need) to get rolling:
A desktop/laptop with Windows 7 or an equivalent OS
A free 3D design software such as Google SketchUp in which the design process is predominantly graphical
- In stark contrast, something like OpenSCAD is more suited to code-savvy designers who like to design models using code instead of graphically sketching models
- Another free option would be Tinkercad that helps design complex parts using simple geometric shapes
A 3D printer with a capacity to print a workpiece 6 in x 6 in x 6 in - I use the Printrbot Simple Metal for this very reason:
- In addition an X-Axis upgrade and a Heated bed is highly recommended for the following reasons:
- During my trials, I had a hard time making large parts stick to the regular bed
- Even if the parts stuck, large parts warped on one side - sometimes severely enough to make the part useless
- Besides, I plan to print parts larger than 6 inches along one axis , at least in the near term
- That said, I'm not a Printrbot spokesman - I got one because of a great holiday deal and simply loved the idea of assembling an entire printer myself
A free 3D printing software such as Repetier or the latest version of Cura , the latter being a lot easier to use.
A few basic tools such as a hobby knife, nose pliers to trim the parts once they're printed
And obviously, the raw material to print - I used 1.75mm PLA Black and Snow White for my first prototype demonstrated in this IBLE - The printer came with a 0.4mm nozzle on the hot end.
- Based on the make and model of the printer, this article presumes that the 3D printer will be operational and ready to print
- I use PLA because it's easier - ABS can also be used, but I haven't gotten that far yet
- Cheap material sourced from overseas may not be the best choice - irregular diameter of the filament and particle contaminants can quickly degrade print quality and clog the nozzle!
Step 3: The Design, Form and Function
As mentioned in my problem statement, the intention was to design something that would meet the following objectives:
- conform to the circular theme and agree with the overall layout
- have a profile that would make it wrap snugly around the tubular steering column
- is deep enough to accommodate the switches and wiring within the form
- Not have rectangular edges stick out and have my foot run into it all the time
With these objectives, I came up with a two-piece design just as most automotive switch panels are but incorporating the following form and function features:
- a shape that is semi-circular making it a lot more compact and not have my foot run into it all the time
- the smaller of the two circular edges on the body and top panel conform with the radius of the steering column making for a better fit
- have space to accommodate 5 switches , or 3 switches, plus a couple of turn signal blinkers
- is deep enough (46 mm) to accommodate the switches and wires within the body
The pictures show the top panel and body with their key measurements - the assembled views were put together to make sure that the top panel and the body would fit correctly once printed.
Step 4: The 3D Printer Setup
Based on the experience with my 3D printer, I had to make changes to some of my settings as described below.
Basic Cura Settings:
Infill Percentage: I wanted a solid part, and therefore, set this to 100%
Printing Temperature: 210 degrees C - for smaller parts I would use lower temperatures
Heated Bed Temperature (when printing):60 degrees C
Initial layer thickness: 0.3 mm
Expert Cura Settings:
Height at which the Fan turns ON:22 mm (for larger body) , 12 mm (for smaller switch panel)
Advanced Cura Settings:
Support: Touching Build Plate
Support Type: Raft
- Subsequent steps will explain the reasons for some of the Advanced and Expert Settings
- In addition, the support type will also influence this temperature setting
- Once the model is loaded into Cura, use the Lay Flat feature of the Rotate tool
Step 5: Initial Failures & Workarounds
3D Printing is definitely not easy and is fraught with failures! Just when you think that you've figured it all out, you're hit with new challenges that need to be resolved even before decent progress can become achievable.
Installing a heated bed doesn't mean printing is going to be a walk in the park! My initial attempts at printing with the heated bed ran into some epic failures as shown in the visuals.
Therefore, here are some of the adjustments that you may want to make.
Preheating the bed to a higher temperature:
- Preheating the bed to a higher temperature before printing makes the first few layers stick to the bed better
- In Cura, you can set this temperature in the "Bed Temp" field - in this case, the value is set up at 80 deg C , 20 degrees higher than the printing temperature value of 60 deg C
- The bed may take a few minutes longer to heat up and the print may take longer to start, but that's better than epic failures!
Turning on the Cooling Fan later during the course of printing:
Starting printing with the Fan ON at the very first layer, simply undoes the effect of the high bed temperature setting. I've had better results with the cooling fan turned on at a much later stage in printing when it reaches a certain vertical height (along the Z-axis)
- This setting can be configured via the Expert Settings from Cura - in this case, the height of the body is 46.00 mm and the fan was set to come on at 22.0 mm, approximately less than 50% of the total height of the work piece
- In case of the switch panel, this setting was set to 12.00 mm
- Which means that almost this entire piece was printed with the fan turned off because a flat piece with a thin cross-section such as this would cool much faster with the Fan ON, increasing the chances of warping
Using the Raft Support when printing:
- A Raft is a thick layer that is laid down on the bed before printing of the actual part commences
- Using this support almost guarantees successful prints, but separating this support from the actual part is easier said then done!
- In Cura, the Raft setting can be set up in the Support section of the Advanced Settings Tab
- Make sure that the Support Type is set to "Touching the Build plate" so that the Raft is laid down only on the bed
Commencing with the Prints
- The last few pictures show the influence of these settings as the initial layer of the Raft is being laid down
- The fan can be seen turned off when the printing commences
- One may argue that an entire part could be printed at a higher bed temperature
- But this may not always work in case of parts with smaller cross sections as elevated temperatures over time may make the PLA highly pliable causing the part to lose form
- These settings are not cast in stone and may have to be tweaked based on the form, function and dimensions of the part being printed
Step 6: The Printing in Progress
The visuals in this step illustrate the printing process of both, the top switch plate and the larger body
As seen from the printing process, the Raft is the bottom layer that is a bit larger then the actual dimensions of the part being laid out on top of it.
But it does assist in making the part stick to the bed and carry it to completion
NOTE ON USING RAFT
- The Raft setting is the most reliable setting to maximize successful prints
- But incorporating the Raft increases print time and consumes additional PLA material - quiet a waste for something that has to be cut off and discarded
- In addition, choosing the Raft can sometimes undermine the functional and esthetic features of the part
- In this case, the top face of the switch panel has been completely overrun by the raft and peeling it away from the face is not worth the time and effort
- Therefore, the real challenge is to get the part to print without the Raft - especially the smaller Switch panel
- But as the heated bed is fairly new, a few more tests with the temperature settings will have to be carried out to achieve this objective
Step 7: Trimming the Rough Edges
Once the prints were cooled, the rafts were removed using a set of Nose Pliers and a hobby knife
The knife is helpful especially when the raft has to be cut out of the openings in the parts.
The dumbbell shaped hole on the bottom face of the body is the place where the wires will pass through.
Dimensions-wise, the prints came out well fitted - there was absolutely no work involved in making the top switch panel fit to its body!
NOTE ON RETAINING THE RAFT SUPPORT
In this application, I decided to retain the raft on the larger body for the simple fact that the weave on the bottom layer would provide additional strength especially because this part has to be mounted on the steering column and tightened.
Step 8: Testing the Fit
Moment of truth! Will the part fit around the steering column?
Yippee! It does fit snug and definitely looks better than the stupid box that's in use now!
In addition to the two main parts, I had printed out a couple of mounting clamps - these were a product of some of my initial practice runs with the 3D printer when I first bought it.
I may not use these because the horn-button (in the last two pictures) comes with an integrated metal clamp that currently holds the square switch panel in place . I plan to use this clamp to secure the new Switch box to the steering column
Therefore, these additional parts have not been elaborated here in this IBLE.
Step 9: Next Steps - Putting the Parts to Work!
Now that the parts are ready, the next steps would be to:
Locating and creating Mounting holes
- PLA is brittle and drilling holes into it when cold may not be a wise choice
- Therefore, I have to think of using alternatives (heated pick maybe?) when it comes to creating mounting holes
Reinforcing the parts with metal
- Metal is metal, and for that reason I may have to use it to put additional reinforcements in place
- Adding flat fender washers to distribute the force on the PLA when tightening the mounting bolts down is one place reinforcements will be extremely helpful
Weatherproofing the parts
- Finally, I may have to sand, prime and paint the parts inside and out to help it withstand the heat and cold cycles of the moody New England weather!
Should this panel crack or break, so be it! I'll simply print another one! Isn't that the fun of 3D printing?
Thanks for reading this IBLE and happy making!