assignments

Assignment

Group Assignment:do your lab's safety training

test runout, alignment, fixturing, speeds, feeds, materials,and toolpaths for your machine

Document your work to the group work page and reflect on your individual page what you learned

Individual Assignment: make (design+mill+assemble) something big (~meter-scale)

extra credit: don't use fasteners or glue

extra credit: include curved surfaces

All the important links are Here

Learning outcomes

Demonstrate 2D design development for CNC milling production

Describe workflows for CNC milling production

Shopbot PRSstandard

This is detailed manual on the machine we have here Shopbot PRSstandard

This is a labelled diagram of the machine here

Image Source

This is the axis orientation of the machine

Image Source

Group Assignment

Do your lab's safety training
Test runout, alignment, fixturing, speeds, feeds, materials, and toolpaths for your machine
Document your work to the group work page and reflect on your individual page what you learned

Here is the Group Assignment

1. Introduction

In this assignment, we aim to explore the capabilities of the ShopBot PRS standard CNC machine, a powerful and versatile platform for computer-controlled machining. We will learn about the machine's specifications, understand its safety rules, and then model and cut a simple object.

2. ShopBot PRS Standard CNC - Specifications

The ShopBot PRS Standard CNC is a high-quality, precision CNC machine. Some of its primary specifications include:

Workspace: 2400mm x 1220mm
Speed: We used the speed of 10000 RPM to cut our design
Software: The ShopBot PRS Standard CNC machine uses the ShopBot Control Software for operation
Fixture: In our lab, we attach our cutting material to the ShopBot machine using clamps.
Setting origins: In our lab, we set the origins for the x and y axis using the ShopBot3 software. The ShopBot has proximity sensors that detect the extreme points of the material you intend to cut. For the z axis, you have to manually set the origins through zeroing. The zeroing process for the ShopBot is different compared to that of the SRM milling machine. To do zeroing on the ShopBot, you have to place the metal plate that is usually located on top of the drill on top of the material you intend to cut. Then, attach the clip on the end of the plate to the ShopBot.

Emergency Stop Button

Red button: This is the emergency stop button that will immediately stop the CNC. This is mainly used to stop the machine if any problems occur.
Blue button: This is the reset button. This button is used to reset the CNC machine. This is mainly used after turning on the machine as you have to reset the machine before any cutting can be done.
Green button: The green button is the start button. This button, when pressed, makes the endmill start rotating. Remember to always press it before any cutting, otherwise, the machine will cut without the endmill spinning. This may ultimately lead to the endmill breaking.

Main Control Box

This is the main control box. This is where you can turn on your CNC machine. It is also where the wrench meant to open the spindle is kept. It has two inputs: the on/off switch and an engaged/disengaged key slot. The on and off switches are pretty self-explanatory. The key is to either keep the machine engaged or disengaged, mainly so that the person isn't harmed while opening the spindle.

3. Safety Rules

Operating a CNC machine like the ShopBot PRS Standard requires adhering to several safety rules:

Always wear safety glasses and hearing protection when the machine is in operation.
Never leave the machine unattended while it's running.
Keep hands, hair, and clothing away from moving parts.
Always use the appropriate feed rates and spindle speeds for the material being cut.
Ensure the workpiece is securely clamped or drilled before starting the machine.
Regularly check and maintain the machine for loose components and wear.
Never wear loose clothes that might get caught while you are cutting. Also, if you have long hair, always remember to tie it up!
Always have the emergency stop button right beside you so that if anything happens, you can immediately stop it.
If any debris and dust are left over, always ensure that you have cleaned it before using the machine. If you have a dust collector, you don't need to clean, but still check if any dust is being left over!

4. Modeling and Cutting

For our cutting project, we chose to create a simple design. We used Fusion 360 to create the sketch, which we exported as a DXF file and then further improved with the help of Inkscape. Finally, we used the VCarve Pro software to generate the toolpaths and send the job to the ShopBot CNC machine. The process involved:

Creating the Sketch: Using Fusion 360 to design the object.
Exporting the Sketch: Saving the sketch as a DXF file for further processing.
Importing the Sketch: Importing the DXF file into Inkscape to refine the design.
Generating Toolpaths: Using VCarve Pro to create the toolpaths for the CNC machine.
Setting up the Machine: Securing the material and setting the origins on the ShopBot CNC machine.
Running the Job: Executing the job and monitoring the process.

Below are images of the model created in Fusion 360 and the cutting process:

5. Reflection

In this assignment, we learned the entire process of operating the ShopBot PRS Standard CNC machine, from setting up the material to executing the cutting job. Understanding the machine's specifications and safety protocols was crucial in ensuring a smooth and safe operation. The experience of modeling, generating toolpaths, and finally seeing the design come to life was highly rewarding. Through this project, we gained hands-on experience in computer-controlled machining, reinforcing our theoretical knowledge with practical skills.

Individual Assignment

make (design+mill+assemble) something big (~meter-scale)

extra credit: don't use fasteners or glue

extra credit: include curved surfaces

My design

This week is something I have been waiting for since the starting of the fab academy course. I always wanted to use the CNC machine to make a desk organizer for myself, but since its is suppose to be in meter-scale I cancelled my plan. I have decided to make a cat tower for my pet cat. The design I chose is inspired from Lina Hudaib

Let's get started

This is the only parameter I used, one for the hold diameter and the other for the material thickness

First sketch the part and extrude it.

Then I tried assembling it

Then made a stable stand on the edge to support the whole structure

Then comes a place where my pet cat can climb and rest on

Lets download the dog bone addins

For that follow the link and download the Add-in.

Dont forget the dog bones!!

I made two holes for my pet's plate and cup. and there you have it The whole design

Here is a 3-D model of it

Miling!

VCarve

To begin using VCarve, you first need to set the dimensions of your material.After configuring these dimensions, import your design into the workspace and position it appropriately on the defined area. Next, click on the toolpath button to access the toolpath settings. Here, you can adjust various parameters, such as the number of tabs and other relevant settings. Once everything is configured to your satisfaction, you can generate the toolpath. To start, you'll need to create a new file for importing your DXF design. Begin by selecting the option to create a new file, then set the dimensions of your workspace accordingly. After this setup, you can proceed with importing and adjusting your design, followed by configuring the toolpath as needed.

After setting up the dimensions, you'll have a file that matches the size of your cutting material. It's crucial to measure your cutting plane accurately to avoid issues during the cutting process. Properly measuring the thickness is equally important; incorrect thickness can lead to significant problems. If the thickness is underestimated, the design won't be cut through completely. If overestimated, the design may come loose before the cut finishes, potentially causing the mill bit to jam and break.

Image Source Thank you Thinley Wozer for the image.(I forgot to take a picture of mine)

Next, press the toolpath button and select the profile cut toolpath. This toolpath is used to precisely cut through the material in the shapes specified by your design. Note: you should adjust the toolpaths only after your design is fully set up. It's important to ensure all design elements are correctly positioned before modifying the toolpath settings.

After changing the above settings, always double-check your work. Ensure that you have added the necessary tabs. This step is crucial to maintain the integrity of your cut pieces during the machining process.

Image Source Thank you so much Yangtshel! You have always helped me!

Finally, save your design and proceed to configure the machine settings using the ShopBot3 software for the cutting process.

Image Source Thank you so much Yangtshel! You have always helped me!

Now the real miling!

Shopbot

In the previous step, we generated the toolpath for the CNC. Now, let's configure the machine for cutting. This mainly involves setting the machine's origin points. The X and Y axes can be set manually or automatically adjusted to the edge of the workspace using the auto-origin function. The Z-axis, however, requires manual adjustment.

Begin by securely attaching the alligator clip to the machine.

Image Source Thank you so much Yangtshel! You have always helped me!

Next, press the Z-axis zeroing button in the ShopBot3 software. This action will cause the endmill to slowly descend. Make sure the metal plate is correctly positioned on the material bed before doing this.

Video Source Thank you so much Yangtshel! You have always helped me!

After the zeroing process is complete, make sure to return the clip to its original position. With the machine setup finished, you can now proceed to print your design.

Processes to mill

First, press the start option to initiate the cutting process. After clicking the cut button, a prompt will appear asking you to turn on the spindle and ensure the vacuum is activated and ready for the cutting process. Use the designated button to start the spindle.

Image Source Thank you so much Yangtshel! You have always helped me!

RED button - The red button serves as the emergency stop (press this if any mishaps occur during the cutting process).
GREEN button - The green button is used to start the spindle (press this to initiate the spindle and begin cutting).
BLUE button - This is the reset button, which resets the machine (use this immediately after powering on the machine).

Next, we need to activate the vacuum by pressing this button.(tHE RED ONE)

Image Source Thank you so much Yangtshel! You have always helped me!

Milling Process

Dont forget to clean after use!

Outcome

And yes, the outcome is not as expected

The black cloth is supposed to depict a cat, and the holes are where the plates go.

The reason why my design failed is beacuse I didn't pay close attention to detail for th design I had made in Fusion360. After milling my dsign I went through my fusion design again and found that I had the slots made in wrong sides. The intersection point for my triangle was not aligned. Therefore, it was design that had caused the whole thing to be unsuccessful. I would be designing a new idea to fulfil the assignment needs.

New Design

For the new designs I thought of doing two designs. And fabricating any I liked most

For the first new design, I decided with a shelf like the one below

Image Source

Lets get started!

Firstly, I started by starting with the parameters

I got the following parameter idea from a youtube video

I will be changing the parameters in the end when I am finally printing.

Now start by making the first sketch.

This is going to be the side supports for the overall shelf design

The first sketch should come out like this.

Now extrude the top part of the shelf. This will be the flat top/lid for the shelf

Since the side supports need to be solid and rigid to have slots for the shelf compartments, extrude the overall sketch.

You need the exact same side support for the other side so you will need to construct a midplane for the body to me mirrored past that plane.

Now for the next step, to not cause inconvinience you can turn the visibility off for the bodies that you will not be needing.

Then project your whole sketch

Now, you won't be needing the first sketch, and can work with the projection made

For more accurate design, instead of having to drag the body while extruding till where you want to extrude it. You can simply use the "Extent type", "To Object" to craete more accurate extrude.

To boost my motivation to design. Now, I will change the appearance of the model to wood.

Now we will create tabs. We can firstly start with the tabs for the kick.

Now do the same for the side support bodies.

Now, the base of the shelf or the lower compartment

Now the upper shelf compartment, just use the mirror tool.

Now, the back part of the shelf.

Now we will use the presspull tool, since right now there are no excess spaces for the tabs created. After using the presspull tool, there will be space between the tabs created and the edges of the body.

Since we finished creating the tabs for the parts in the model, we also need to create slots for the tabs. To do that we can simply use the "Combine" tool and and cut through accurate slots for the tabs.

Since, it is essential to create dog bones, I laid out the parts flat on the surface and selected all as one to make my work easy.

Since I created the design a little too big, I adjusted my parameters and decided to go like this for the compartments. It can be used as a bed side table.

For the second new design I decided on a simple table.

Its like a study table for me

Since I had already designed a shelf before this. I wanted similiar dimensions for my table. So I just sketched on top of the previous designs and extrude a new component.

Here I chose the legs of the shelf and used a circular tool to make the legs of my table. And went with the same tab size and dimension.

Then for this part of the table, for the tab I simply used the material thickness as the width and kept the length just smaller than the component itself and extruded it. Then like in the shelf design I combined the shapes using the combine tool but "Cut" as the tool type.

These are the dimensions I considered while designing the tabs.

To get accurate and perfect duplicate of the componet I used the mirror tool like in the shelf design.

As for the top component of my table, I simply created a rectangle and extruded it with the dimensions of the material thickness and combined the shapes using "cut" as the tool type in the selection. And now I am done with the sketch.

Bringing my fusion design to life!

The Final Outcome

Reflection

Initially, my goal was to create a unique and functional cat house. However, my first attempt was unsuccessful due to misinterpretations in the parameters and a lack of close attention to detail. The problem became apparent only after the fabrication was complete, highlighting a crucial lesson about the necessity of meticulous planning and verification before proceeding with machining.

Determined to fulfill the assignment successfully, I decided to design two additional projects: a shelf and a table. These projects allowed me to refine my skills and apply the lessons learned from my initial attempt. Designing and fabricating the shelf and table not only provided me with practical experience and also helped in enhancing my experience with fusion.

This week has significantly enhanced my designing skills. The journey from failure to success was both challenging and rewarding, as it taught me the importance of precision, patience, and perseverance. Despite the initial setback, the experience has been immensely valuable, contributing to my growth as a learner.

A very big Thanks to Yangtshel Wangyel for helping me this week. I really appreciate your effort for teaching me the ShoptBot milling process.

Files

My .dxf file for the cat tower

My.dxf file for the Shelf/Bedside table