Kids Car Plywood Laser Cut Tot Rod

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I always liked small cars, thats why i own a daihatsu and also a fiat 126. But they weren't small enough so i wanted to build something smaller.

Firsth I've thought of building the car by using a 3d printer. I saw 3d printed cars on the web and planned to go towards that way. I've thought that my favourite car the fiat 126 would be appropriate for the outer bodyshell of the car. Approximately 1:2 size would be good, making the final mini car to be 1.5meter long.

Step 1: Micro Chassis First

To test the feasibility of this idea, I firstly designed and built a 30cms version. I designed all chassis and bodyshell parts in Solidworks. I've tried to make the design as 3d print friendly as possible. Then printed all the parts, assembled them, developed the necessary electronics and microcontroller code to run and test the car. This also turned into a very fun and big project on its own which deserves having its own instructable. Which i plan to write soon.

This initial project helped a lot to the design and testing of the embedded firmware to drive dc motors for wheels and a servo or DC motor for steering. The micro car is mainly remote controlled but it has ultrasonic obstacle sensor inputs and capability to make decisions upon those inputs therefore is able to sort of steer and drive itself.

During the production of this 30cm micro car, the time required for printing was so long and processing parts was so boring and difficult i realized that 3d printing a 1.5 long car would be almost impossible for me with the capabilities at hand such as my small Anet a8 3d printer and the makeshift workshop which i currently have access to. So i decided to modify my design for laser cut plywood production and have a professional company do the cutting.

Step 2: Converting the Design to Laser-cut Plywood Construction

During this phase i still hoped to leave some parts of the car for being manufactured by 3d printing as they were ready as 3d models. They were mainly some parts at the steering and motor coupling with smaller but important details or spheric forms which would be hard to produce with laser cut plywood :D .But I modified the rest of the chassis parts for laser cutting.

As the first step in this process, I've upscaled the 30cm micro version to 1.5 meters as it is then started cutting up and reshaping the enlarged chassis parts in solidworks.

I upscaled and reshaped the bodyshell also, chopped its roof to enable a larger person to be able to sit in it. I planned to slice it to smaller pieces that can be printed in a 3d printer with a smaller print volume such as 20x20x25cms.

Designed the seat, chassis base, other load bearing parts all from 12mm plywood.

I left some gaps just in front and behind of the front-rear axles to enable the chassis to flex at those areas creating some sort of suspension with the flexibility of plywood.

I incorporated many assembly details in the plywood 3d model for simplifying the assembly process. I wanted the asssembly to be a bolt-on screw-in type process without any modification, cutting etc .

Step 3: Laser Cutting the Parts

Then I've sent the DXF files to a firm for laser cutting. The parts arrived within a week and they were perfect. I can imagine the time and effort required if I tried to cut the parts manually. Almost unthinkable.

Checked the parts, removed some excess pieces inside the holes etc and did a quick assembly at home. That was quite fun, easy and promising. liked it.

Step 4: Assembly of the Chassis

I disassembled and took the parts from the office to my workshop and assembled them by using bolts and nuts. A power drill helped a lot.

The wheels are standard hand cart wheels with approximately 30cms in diameter and 20mm bearing axles.

Drive motors are chinese made kids car motors which can be purchased from aliexpress.

Aliexpress link for the drive motors

There are many sellers who sell similar motors, here is an other one, and an other one, and an other one.

I've uploaded the renderings of the 3d models for the motors i've used also the web pages of the sellers i've bought. But any similar motor is quite adoptable to the design as its plywood material is very easy to work on and modify.

I've also used a third motor for steering as the vehicle will also be remotely controlled. That motor can also be found at the above links.

There are also sellers who have complete sets with all the motors, wiring and electronic hardware for driving them. They even have remote control ready. Here is one.

The coupling parts between motors and the wheels are also sold in Aliexpress. I've preferred to make my own designs and 3d print them. But you can just goto the site and order. They are probably much stronger than a 3d printed part. Here is the link.

In fact all the motors are optional, as this kids vehicle can also be made without any motor as a push powered model.

Step 5: Steering Setup

The steering uses six 3d printed parts, two spindles for both sides and rod head pieces two on each side.

Printed them by using my Anet A8 then moved on to the problem of transferring steering wheel's turning action to the front wheels. I considered several ways of doing that but finally decided upon this one. The two ends of a thin but strong sailing thread wound around the steering wheel shaft are connected to the ends of the steering rod and when the steering wheel is turned, the thread is wound and unwound around the shaft, pulling the rod towards the turning direction. It is simple and effective. works ok for now.

As I had some difficulty in printing these larger parts, I've reduced their sizes in the 3d model to make production simpler. I also made additional plywood parts to be used instead of 3d printed parts. I've put on both options in the 3d model and plywood cutting plans to give later builders the option to choose between two options.

Step 6: Rear Axle Assembly

The motors are in a thru-axle form. They are planned to have a solid axle passing thru them to carry the weight of the car. So I've purchased an aluminum pipe of 12mm diameter for that purpose. A steel one could also be used. As I have an alu metal seller near, I've chosen to use alu. it is also lighter.

I've used bolts and nuts as usual together with some steel U clamps to secure the axle onto the chassis.

Then inserted the motors on each side of the axle and secured them with screws onto the holes present on the plywood supports at each side. Then inserted the 3d printed coupling parts to transfer power from the motors to the wheels.

As the shaft diameter of the wheels is 20mm and the inside diameter for the axle is 12mm (due to motors' hole size for the axle) I made two distance parts in solidworks and 3d printed them. They are for enlarging the axle from 12 to 18mm. and for the remaining 2mms I used the small parts I've cut from a steel pipe with 20mm diameter. I've glued the parts and inside each other at the ends of the axle. Applied some grease to the outside of the 20mm steel pipe and slided the wheels on. Used some wide metal washers and hose clamps to hold the wheels in place.

Step 7: Front Axle

This is the area where most of the 3d printed parts are located. Two spindles and 2 parts for each rod end, 2 + 4=6 in total. I used large bolts as king pins and screwed the spindles onto the chasis. Used nuts with plastic resistance elements inside for a secure and not self-loosening connection.

I've cut pieces from the 20mm diameter steel pipe for the front axles and placed them into the holes of the 3d printed spindles. Glued them together with wide steel washers that will protect the 3d printed spindles from the friction of the wheels.

applied some grease to the axles and slided the wheels onto them. Similar to what i did at the real axle, I used metal washers and hose clamps to hold the wheels in place.

Step 8: Completed Chassis

The chassis is now complete and standing-rolling on its wheels. It is quite light and strong.

After working with plywood this much, i liked the simplicity and fun of it and thought may be i can also make the bodyshell with laser cut plywood. As the Fiat 126 is a quite boxy car, i thought it would not be so difficult to make a body for it by using sheet material.

Even so , i decided to give it a try first and model something even boxier than a fiat 126.

Ah yes, a Minimoke seemed like a really good choice for that.

Step 9: Minimoke Bodyshell

The Minimoke is a real gem. A small and cute off(?) roader, beach buggy and it has mostly flat body parts, perfect for production by using sheet material.

I've found some photos from the net and the blueprints of the vehicle for 3d modeling.

I've cut and adjusted the images for front, rear and side views of the car, scaled them to match my chassis and placed them at sketch backgrounds in Solidworks. Worked on them for quite some time and produced the plywood cut model. I've placed assembly details and holes for each and every part, also added very precise holes and details for the bodyshell to be assembled to the plywood chassis.

Finally I laid the parts on a standard plywood sheet and arranged them for manufacturing with minimum material loss. Half of a standard size sheet is enough for the whole parts.

While I was just about to send the DXF cutting files to the laser cutting firm, I thought may be a Land rover Defender can be a good option to be placed on my chassis too. I delayed the order and started working on the Landrover bodyshell to see how it will turn out.

Step 10: Land Rover Bodyshell

I always liked Land Rovers, a frien of mine had one and while i was living in a foresty area of our city, he used to visit and we used to goto trips in the dirt roads of the forest. It was fun.

An other good option as a bodyshell to my chassis.

I've searched the net and found some photos and the blueprints of the vehicle for 3d modeling.

I've cut and adjusted the images for front, rear and side views of the Landrover, scaled them to match my chassis and placed them at sketch backgrounds in Solidworks. Worked on them for quite some time and produced the plywood cut model. Similar to Minimoke, I've placed assembly details and holes for each and every part, also added very precise holes and details for the bodyshell to be assembled to the plywood chassis.

I've modeled extra parts for this bodyshell to be manufactured with details of a Series 1, 2 or later LandRover Defender, all matching each other.

Finally I laid the parts on standard plywood sheets and arranged them for manufacturing with minimum material loss. two standard size sheets are required for all the parts.

I also made the option to produce mudguards by using plywood and also 3d printed abs plastic.

Step 11: Escort Mk2 Bodyshell

Then i showed my designs in some online forums and people told me a Ford escort mk2 would also be good :) I liked the idea and started working again. Oh my god this project will last forever.

I've searched the net and found some photos and the blueprints of the mk2 ford escort for 3d modeling.
I've cut and adjusted the images for front, rear and side views of the car, scaled them to match my chassis and placed them at sketch backgrounds in Solidworks. Worked on them for quite some time and produced the plywood cut model. Similar to LandRover, I've placed assembly details and holes for each and every part, also added very precise holes and details for the bodyshell to be assembled to the plywood chassis. For the bonnet, roof and the sides, I made curved details for the first time taking advantage of plywood's flexibility for a model more matching the lines of the escort design.

Finally I laid the parts on a standard plywood sheet and arranged them for manufacturing with minimum material loss. One standard size sheet is enough for fitting all the parts.

Step 12: Citroen 2CV Bodyshell

And while producing i thought of continuing and making some more options. My next choice was the Citroen 2Cv prototype. Having quite flat surfaces and details, this car was also very suitable for sheet material production. As it is seen on the prototype photos, in fact it seems like produced from sheet ply :D

I did the same, searched the net for blueprints but there were none available. So used the blueprints of a later production 2cv and mixed it with the details I took from the photos of the prototype. It turned out quite well.

Similar to the previous designs, I've placed assembly details and holes for each and every part, also added very precise holes and details for the bodyshell to be assembled to the plywood chassis. Finally I laid the parts on standard plywood sheets and arranged them for manufacturing with minimum material loss. two standard size sheets are required for all the parts.

Step 13: Fiat 126p Bodyshell

And finally it was time to work on my first target the Fiat 126p.

I've searched the net and found the blueprints of the Fiat 126p and started 3d modeling.
I've cut and adjusted the images for front, rear and side views of the car, scaled them to match my chassis and placed them at sketch backgrounds in Solidworks. Worked on them for quite some time and produced the plywood cut model. Similar to previous models I've placed assembly details and holes for each and every part, also added very precise holes and details for the bodyshell to be assembled to the plywood chassis. For the bonnet, roof and the sides, I made curved details similar to my escort model, taking advantage of plywood's flexibility for a model more matching the lines of the escort design.

This one turned out quite ok too. I'll send it to laser cutting soon.

Or maybe i should build the minimoke? or the escort, or land rover.

oh difficult to choose, maybe the 2cv prototype.

what do you think?

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