The TSN BasicBot is a platform for STEM students to develop an array of future-ready skills that demonstrate mastery of key science and engineering concepts in the classroom. BasicBot is a scalable, multilevel chassis that is easy to manufacture, build and modify. It has the capability to transform from a simple teaching platform to a combat ready sumobot in short order. With the BasicBot project, students will become proficient at a large number of STEM skills from writing code to advanced manufacturing. BasicBot is designed primarily for use with standard hobby servos and an arduino microcontroller, but thanks to its versatile design it can accomodate a variety of other options. The chassis can be manufactured from a variety of materials, including wood, plastic, acrylic and metal. Teaching students advanced manufacturing is a key STEM skill, and the BasicBot provides an opportunity for teachers to get students comfortable using Computer Aided Manufacturing software due to its simplicity. In this STEM lesson, we will use SprutCAM software to prepare the BasicBot design for manufacture with a CNC vertical milling machine. The instructions are based on the .igs file supplied in this tutorial. The entire CAM process can be viewed on the video at the end.
Step One: Load the Model and Import
Import the .igs model into SprutCAM and save the project.
Step Two: Transform Axes
Sew the faces together, and click the transform tab. Locate the Z axis to maximum. The default settings for X and Y will be fine.
Step Three: Drilling Holes
Create a drilling operation by going to the machining tab. Choose hole drilling. Next, click job assignment on the bottom left of the screen. Drag select the holes that need to be drilled in groups. Be careful not to accidentally select one of the slots or outer edges. Add these to the job assignment by selecting center.
Manually select the faces of each hole on the outer perimeter of the chassis. You can add each one to the job assignment individually or hold down the ctrl key and multiple select them.
Double click on the hole machining operation to edit the parameters. You will need to set the appropriate tool from your tool library, the Z retract height, and the (-Z) drilling depth.
Hit the run button to generate the toolpath, then simulate the operation.
Step Four: Slotting
The slots in the model allow for wire passage and more versatile component placement on the BasicBot. To create the slots we will create a 2D contour operation. In the finishing tab click on 2D contouring.
Make sure that the edge tool is highlighted on the upper right of the SprutCAM screen. Select the job assignment tab on the bottom left of the screen as before. Choose the edges of each slot while clicking the ctrl key.
Click add curves after each complete set of slots. Make sure there are no gaps or SprutCAM will not generate a toolpath. Set the parameters for the job by double clicking on it. This includes selecting the endmill you will be using, feeds and speeds, depth of cut, and so on. More details are provided in the accompanying video. Run the operation to generate the toolpath, then simulate the operation. If it checks out, move on to the final step.
Step Five: Final Cut
Create another 2D contour operation as shown above. This time select the outer edges of the chassis for final cut out. Add to the job assignment as before and generate the toolpath.
Consider using a smaller endmill for making nice sharp inside corners if available. Parameters will need to be adjusted before hitting the run button and doing the final simulation with all operations.
Using CAM to prepare for CNC manufacture of the BasicBot chassis is an excellent introduction to advanced manufacturing for students. Take advantage of SprutCAM America‘s offer of a substantial classroom discount for this powerful and easy to use tool. This series of BasicBot STEM tutorials will continue with further CNC component manufacturing, as well as programming and other lessons to maximize use of the BasicBot to make your students future ready for STEM Now.
Author: Al Chirinian