Computer Numerical Control Machine Design
What is a CNC Router? A CNC Router is a machine that uses Computer Numerical Control (computer coordinates) to take a 3D computer model and create a physical part. CNC Routers generally are used with soft materials, such as wood, plastic, and sometimes aluminum. CNC Routers are great for creating engravings and profiles, such as skateboards, skiis, and signs.
Currently there is a CNC Router at UNR; however, it is nothing more than a table (complete with spindle and motors) and a box of electronic parts. UNR will benefit greatly from a working CNC Router. While there are a number of CNC Mills and other tools in the lab, they are small. limiting the pieces that can be created. This router will be able to create skii profiles, cut high mileage vehicle panel profiles, and perform various other tasks students currently have to perform by hand. This router will create additional educational opportunities for University of Nevada-Reno faculty and students.
The Master Millers got the dismantled CNC router currently residing in Palmer Engineering Lab 2 working properly! The software has been upgraded to Mach 3, a more user friendly and stable program. Also, physical aspects of the router have been improved.
Additional Major Changes implemented:
- A spindle cooling system. This will cool the spindle or router head to prevent the machine from overheating and burning out bearings
- T-tracks integrated into the deck. This will easily allow clamps, fixtures, and bolts to fasten items to the router deck so that they do not move during machining.
- A vacuum system. This system will collect dust and particles while the machine is on and allow the user to clean up the router area afterword.
- A desktop computer. This computer will have all necessary CNC software installed so users just have to bring their part on a flash drive and click start.
Proof of Concept:
- 3 Gecko Stepper Drivers
- 1 C11G Breakout Board (Main Control Board)
- 1 USB Smoothstepper
- 1 Linear Power Supply
- 1 DC Power Supply
- 3 Stepper Motors
Of these components, the following had an electrical short, blown component, or other issue:
- 2 Gecko Stepper Drivers
- 1 C11G Breakout Board
- 1 DC Power Supply
The CNC Router needs a lot of work. While the mechanical components are assembled and functional (as shown by the Proof of Concept), many new electrical components are needed. The team plans to upgrade all the electronic components rather than just replace them. This way, UNR will have a more robust router than the original design.
The first upgrade is to the electronics. Above is a picture of the stepper drivers. On the right is the Gecko driver. On the left is the new Keling driver. The Keling drivers cost approximately one third of the Gecko drivers; however, they are about five times bigger. Luckily our control box will have space to spare, even with the larger drivers.
Next, the router can currently only route materials shorter than 3 inches in height.The team has devised a creative way to easily increase compatible material height to 6 inches. Best of all, this modification is entirely free and requires only some elbow grease.
Finally, the Master Millers will be adding T-slots, shown below, in the table that will allow for items being fabricated to be secured properly and at various locations in the table. This no longer restricts the material to being clamped at the edges of the table. T-slots can be fitted with various types of clamps, and even bolt fixtures, allowing for nearly endless clamping options.
Images directly above: Table top with T-slots that can utilize various clamp types
After the design was finalized, fabrication needed to begin. Three main components need fabrication: the control box, the gantry backboard height, and the t-slots.
Control Box with Electrical Components Mounted
The first thing the Master Millers needed to accomplish was to rewire the entire electrical system. This took the the most time mainly since every component was triple tested to ensure that the wiring was done correctly. The team had already experienced their fair share of electronics failure and wanted to make sure they didn’t cause any additional failures! All of the electrical components were placed in the control box, shown above, so that the components will be protected from damage. Once the control box was completed, the initial configurations needed to be input into Mach 3. This was especially time consuming and difficult due to the teams limited background in programming.
Increased spindle up and down movement
The Master Millers decided to increase the height of objects that can be created. Initially, it was thought that this would involve a great deal of extra labor; however, the team devised an economical solution. By removing the gantry bolts and shifting the gantry upward, the team didn’t have to re-drill the gantry side plates. Overall, the z-axis increase took less than an hour to complete. Because the gantry was over-engineered to begin with, reducing the bolts holding the gantry in place has little to no effect on the overall strength of the gantry supports.
Finally, t-slots were added. This was one of the most difficult and important add-ons. The t-slots will allow for various type of clamps and fixtures to be used to secure parts to the table. To install the t-tracks, the CNC router itself was used!The picture above shows the CNC Router head cutting the slots for the t-tracks. Unfortunately, the t-tracks were longer than the side-to-side travel of the gantry head so the CNC could only be used to create half of the t-track channel. The rest of the channels were manually cut with a wood router.
Picture above shows manual CNC Router used to finish cutting t-slot tracks.
T-tracks installed! Clamps and fixtures can now be used to hold material to router table.
After speaking with Dr. Geiger, the team discovered there was extra money in the budget! The team began planning to implement a vacuum/dust removal system. The logical choice was an affordable, powerful Shop Vac. This will allow the user to clean up the working area during and after use. The picture below shows a picture of the vacuum hose system.
A closeup of the router gantry and spindle is shown below:
The CNC Router is finally complete. What was once a wooden table top with metal legs is now a functioning and capable machine. Look below to see the people who made this happen!
Meet the Master Miller Team:
Justin Sipe is a Mechanical Engineering student at the University of Nevada, Reno and the team leader for the Fall Semester of the Master Millers. Justin enjoys many outdoors activities, such as hunting and wheelin! Justin is also passionate about working on and upgrading his Jeep (Just Empty Every Pocket ). Using his extensive knowledge base and experience working with CNC machines at Hamilton Robotics; he will be able to lead the Master Millers to successful project design.
Kevin Bader is a mechanical engineering student at the University of Nevada, Reno. Born and raised in the Reno area, Kevin enjoys many outdoor activities that Nevada has to offer. Kevin has worked as an intern for a large cold rolled steel company out of California, providing real world experience to apply to future projects. The combination of education through the university as well as the hands on experience through the internship and working on cars gives Kevin a unique skill-set to accomplish engineering tasks.
Tyler Baumgardner is a mechanical engineering student at the University of Nevada. He has been a resident of Reno, Nevada for 16 years. Working for the past 2 years at Hamilton has provided him with a broad view of aspects of the engineering field. He brings knowledge from years of racing motocross and working on cars as a teen as well. From wakeboarding, hunting, climbing, to alpine ski racing, Tyler loves to enjoy the great outdoors that the area has to offer.
Britni Beck is a senior Mechanical Engineering student at the University of Nevada, Reno who is scheduled to graduate in the Spring of 2015 and is the team leader for the Spring Semester for the Master Millers. She has been a resident of the Northern Nevada region for the past 20 years. While working at a grocery store, she has gained experience in management and organization. She has a broad education base that allows her to adapt to various challenges and conquer those challenges successfully. She is a great asset to the Master Millers team.
Ralph Revilleza is a Mechanical Engineering student at the University of Nevada, Reno. He has lived in Reno, Nevada for 14 years . He currently works for Fedex Freight as a certified forklift and hostler operator. Aside from his educational knowledge base, Ralph uses his passion and background from working on his own cars and racing in Motorsports as an asset, which makes him mechanically inclined. This enables him to be more efficient in hands-on types of environment.