Mechanical Design, Machine Design

April 6, 2024

Challenge

• Group assignment:

  • Design a machine that includes mechanism + actuation + automation + application.🥴
  • Build the mechanical parts and operate it manually.
  • Document the group project.

• Individual assignment:

  • Document your individual contribution. 😫

One of the stressful assignment as I’m the only student in the (Node) so I had to find a partner in this project. So After looking one of my work colleges agreed to help in the process of making the machine “Alhamdollelah”. Mahmoud contribution is going to be in the design of the machine and the machining process using the Shop-Bot. Me my self I will be responsible for the entire process from gathering the material, purchasing the parts, finding the suitable specification and assembling the electronics, In addition to the coding process. Mahmoud will help also in the process of assembling the machine together especially the mechanical parts (gears and parts alignment).

Mahmoud is a mechanical engineer he works as a technical support and machine operating in studio 5.

Let the Fun begin –> 🤥

As always every process starts with the research about what we are going to make and who has a contribution in the field before.

• The process started with an argue about using normal plastic for 3D printing I was against this as plastic is a toxic material and when it exposed to heat many harmful particles will be thrown in the air and it might cause serious problems for the one who will inhale it. In addition to that its not efficient to re-form plastic and use it in 3D printing process as buying the PLA is cheaper, as 1kg of filament will be around 14US$. Which is nothing compared to the cost of the plastic bottles needed to produce this amount of filament.

• 1 kg of filament = 335 meter according to this documentation.

• If we consider an average 1.5 liter bottle will give us around 3 meter of filament that means we need around 100 bottle to have the same length of a 1KG spool, (This is not a correct comparison because the density of PLA (1.24 g/cm cubic) different from the density of plastic (1.3 g/cm cubic) this according to {International Bottled water Association}).

• For density please refer to this LINK.

• 100 bottle is a big number of bottles to be processed.

However this was my thoughts about the topic but my friends convinced me in a different way (It is already existing just give it a try.)

• They showed me this video 👇

And from here the story begins.

Research

• At the beginning this machine is called PETmentor.
• I found many people have built it and used it before.
• The machine is very simple to build but it needs patience and accuracy when building it.
• I have found open source project to build this machine –> Link.
• The machine require different moving parts. –> Link.
• I have not found all the parts locally especially the thermo-controller and the motors so I have to find alternatives.

What the machine is doing

The machine will use old plastic bottles and slash them to be then re-formed to plastic filament.

Materials

2 Weeks plan

• The research took almost 1 day and a half starting from Thursday (March - 28) after the session.
• During the research all the needed material listed and prepared for purchase.

Note : Most of the tasks are done in parallel especially the 3D printing and the machining process.

The entire machine building process took 5 days of work from Sunday (March - 31) Until Thursday (April - 4)

Each working day was between 10 to 12 hours in the LAB.

All the research and coding are done home.

• Note the 3D printing process took almost 21 hours printing time if we add the preparation time of the parts it will be around 30 hours as some parts took extra editing we will come to this in the documentation below.

Finding the Parts and order what is needed.

Power Supply

• As for the powering of the machine I have found a Scraped old computer Power Supply.

• This power supply provides 3 different voltages (3.3 , 5 , and 12 volts).

• In my case I will only need the 12 Volts connection.

• The 12 volt wire Is the Yellow one which is going to be the main power connection for me.

• I will Also use the green wire to switch on the Power supply.

refer to this link for more Information about the ATX power supply.

Ramps Controller

• Then I found an old 3D printer controller not used and its not working.

After checking the controller I found its Ramp 1.4 (I have never used it before).

• The controller is a shield that can be attached to Arduino Mega.

For more Information About the controller refer to this LINK

• I have used this shield as a temperature controller as I have not found the thermocontroller needed locally.

• I have connected the shield to an old Arduino Mega and managed to configure it correctly then I tested It using the heat block to check whether it gives accurate data or not.

Doing this test gave me More Understanding about the needed current and how the block is going to work.

I need around 3.2 AMPs only for the block to be heated up, So I had to check the Power supply if it can supply this amount.

For sure the power supply is capable to do this as it can provide 18 AMPs on the 12 Volt part.

The power supply can provide around 216 watt and the heater wire needs 50 watt to works as per the supplier site.

What I have done here exactly is I used an Arduino Mega and I have connected the ramps shields to it then I have programed it.

• I used Marlin 1.0.2-3 frameware And I have used done modification to the code to have the LCD works.

Code I used LINK part 1 LINK part 2 LINK part 3

Just INstall the files and extract them then access the code and then Just upload it.

• Now In the code we need to un-comment these lines.

LCD Graphic

LCD Graphic2

• Now We will just upload the code to the Arduino Mega and the screen should be working properly.

Now this system will control the temperature on its own and keep it within the required range which is between 215 and 220.

Our heat wire is 50 watt which means it can reach 340 degree if this has been connected without a controller which might melt my plastic.

By doing this the Microcontroller will handle the heat and prevent it from exceeding the pre-selected temperature.

Geared DC Motor

• The Motor I needed is out of stock locally.

• So I tried to find similar one but unfortunately the one I found is not working and also different in dimension.

• So I opened it all apart and found one of the gears blocked due to broken shaft holder piece.

• I cleaned it and greased it until it finally worked.

I have ordered the rest of the parts They cost me 230 QAR –> Around 64 Dollar.

Design stage.

In this stage I will be using one of the open source designs available –> LINK

From This tutorial I will Only use the Cutter files as I have tried to use the motor bracket but it did not fit as the motor is different.

• So Mahmoud had to design the part from the scratch.

• The part and the base of the machine designed using ON-Shape.

• The motor has 2 parts Front mounting and back case mounting.

For more Information About drawing sketches in On-Shape Please refer to this LINK

• After the printing of the Case –>

• Also the base of the machine designed using ON-Shape

In the base we used the joint technique without fasteners.

For more INformation about how to build such structure please refer to this LINK

3D Printing and Machining

IN this stage I have 3D printed all the required parts and Mahmoud done the machining of the base.

• As staged before I have only took the cutter part from the open Source project and also the spool of the filament.

• I used Cura to nest the files and Ultimaker S5 to print them.

The files needs around 19 hour which is so long so I left it overnight.

• Also I have printed the Motor files at the beginning but they did not fit as stated before so I had to re print only the fit mount.

As seen it took around 21 Hours to be printed.

Alhamdollelah I have 2 extra printers I can use.

• Motor mount after design.

• 3D print Done.

Raw Files
Motor back
Motor Front
Cutter Files
On-Shape

Machining

In this part the base of the machine fabricated using the Shop-Bot.

We used Aspire for toolpath generation.

For more Information about how to use the machine and how to do the toolpath in details please refer to this LINK

Raw Files
base drawing
On-Shape

Assembly

In this stage we will assemble each part alone and test it then we will assemble the whole machine together and test it.

All the 3D printed parts ready and the component also.

• Now I will start with assembling the cutter base.

• Then I will test it if it works as needed.

Alhamdollelah it works perfect but I need only to grease it to make the movement smother and to give the gears more life span.

• Then I will assemble the PWM part which is going to control the puller motor, in addition to the button of the cutter to rise it and lower it.

Most of the time the cutter will be set on 8 mm height so we can produce fine 1.75 mm filament.

• This part is so simple it consist of two buttons and the PWM.

• Now at this point I will test the entire PMW with the cutter button if they are working after I have soldered it.

Now The puller motor and the cutter works perfectly.

The heater we already tested it before with the Ramp board and it was perfect.

• Now we will assemble the machine all together.

• I will start with the power supply placement as it the heaviest one (I will try to put it in the middle so the weight is distributed in a good way).

• Then I will place the cutter base and the ramp board and I will fasten them to connect the wires.

• Then I will connect the main switch for the machine.

• Then I will connect the PWM and connect them all together.

• THen I will fasten all the bottom parts so I can move to the top parts.

• Now all the parts at the bottom are secured and will managed.

• At this point I will flip the machine and start assembling the top parts.

• I will start with the cutter part.

• I will assemble the cutter case and I will insert the blade inside.

We have to be careful as the blade is so sharp any mistake might cause injuries.

• Then I will make sure the blade height is 8 mm from the machine base.

• Now the cutter part is ready and We will use it as a reference for the other component to be aligned with.

• At this part Mahmoud will do his magic to make sure all the other parts are on the center as he designed.

• Now all the steps are clear and every thing will be only assembled and fastened at the center line.

Testing the machine

• The machine is very quite easy to operate.

• We need to cut the plastic bottle from the bottom and take a small strip and move it inside the cutter case to have the desired width.

• Then we will cut the front end of the strip as small as possible and get it inside the back of the Nozzle until it come out from the front side of the Nozzle.

• At this point we can start the heating process and pull the front end of the stripe until we connect it with the spool.

• Then the spool will take it from here and pull the strip.

• When the strip is coming from the front of the spool and the heater is working don’t wait until it become hot pull the strip and extract what is coming out and try to connect it with the spool and let the spool continue the work.

• Otherwise the plastic may stuck inside the Nozzle and the spool might not be able to pull it out.

Don’t pull with extra power it will break and you have to go from the first step again and wait the heat block to cool down a bit.

• Here we go the machine works perfect.

• The filament is 1.73 mm which is the required.

Future Improvement

• This machine can be made much better by adding an option to change the filament diameter by pre selected options such 1.7 or 2.8 so it has a pre-programmed positions for the knife.

• Adaptive motor torque which can adapt depends on the filament resistance.

• pre-programmed options depends on the bottle length.

• An option to combine two bottles together so we can have a longer filament.

• Making the design of the machine more stylish.

Raw Files
3D Print
Motor back
Motor Front
Cutter Files
On-Shape

Wooden Base
base drawing
On-Shape