During the Milling Appointment

What to Expect During the Milling Appointment

Setting up a job to run on the router can take some time. Be prepared to allow about 30 minutes for this process, sometimes less and sometimes longer depending on the machine being used and the complexity of the job.

1. Examine Material
   1. The TA will look over your material to determine how best to secure it to the machine. It is best if you talk to a TA in advance of your milling appointment to make sure you material is adequately prepared. In some extreme cases, it is necessary for the stock to have pre-drilled holes created, be mounted to sacrificial material, or be processed to create a flatter face.
2. Review Mastercam File
   1. The TA will measure the actual tools you will be using and update that information in your file.
   2. The TA will measure the actual size of your stock material and update that information in your file.
   3. The TA will check over toolpath parameters and make changes if necessary.
   4. The TA will then run a verification of the file to check for collisions or other problems.
3. Create NC File
   1. Once the TA has determined that the file is ready to run, they will then create a file from Mastercam that the CNC router can read. This file is referred to as an NC file.
   2. The TA will then review the NC file to check for errors.
4. Transmit/Load NC File
   1. Once reviewed, the NC file is then loaded to the CNC machine. Depending on the machine you are using and the size of the file, this can take almost no time, or up to 30 minutes.
5. Secure Material to Bed
   
   1. The TA may ask for your assistance in loading your material onto the machine. Pay attention to this part of the process as mistakes are commonly encountered here. Watch to make sure the material is loaded onto the machine in the correct orientation (e.g. the long axis of your file fits on the long axis of the material) and that the correct side is facing up.
   2. Properly securing your material to the CNC machine is required for both safety and model quality. Additionally, some materials can bow or flex as they are being cut, making them more difficult to cut and be securely held.
   3. The Onsrud router has a vacuum table. For most parts, this vacuum is sufficient to hold your part in place and it isn't necessary to make any additional accommodations. Some materials and processes will require that your part be secured with fasteners to a sacrificial piece of material. Hardwood boards often need to be held to the machine using a special vacuum grid and gasket material. Setting this up can take 20 minutes or more.
   4. The AXYZ machine does not have a vacuum table, so the use of fasteners are necessary to secure the part to the machine. Brass screws are used as they are softer and will cause less damage the cutting tool if there is a collision. However, every effort in preparing the file and setting up the machine should be made in order to prevent this from happening.
   5. More complex milling jobs, such as those milling multiple sides of a part that require the material to be flipped between milling operations, will require additional consideration in securing and locating the the material on the machine. Talk to a TA before preparing material for those jobs as additional fixtures may be required. 
6. Set Up CNC Machine
   1. A number of settings must be made on the CNC machine before a job can be started. Depending on which machine is being used and the needs of the job, this may take up to 30 minutes. Two of the settings which must be confirmed on the machine before every job:
      1. The project origin must be defined with respect to the home origin of the machine. 
      2. The tool lengths must be setup and confirmed in the machine OS.
      3. The override on the programmed feed rate and spindle speed.
7. Monitor the Job
   1. Users are required to stay with the machine while a part/model is being milled. TAs are not responsible for monitoring students' jobs alone.
   2. No one knows or cares about your model/part better than you, so it's in your best interest to remain attentive to the job as it is being milled. Watch the machine as it operates, taking note that all operations are occurring in order and that the correct tools are being used.
   3. Depending on the material, geometry, tools, and toolpath strategy, a lot can happen during the milling process. Materials can delaminate, small parts can break off, material hold can degrade and cause the part/model to become a dangerous projectile. It is important that you and the TA remain attentive to what is happening in the room and are able to respond as necessary.
   4. It is possible to pause and resume a job as it cuts, if necessary, but jobs generally cannot be paused for an extended period of time. There are also emergency stops on all CNC machines, and Emergency Power Off buttons in the CNC control room. If a TA does not point these out to you, please ask them to do so. 
8. Clean up

1. 1. After the job has finished, the users are required to clean the CNC machine and its environs of dust and cut material created during the job. Do not climb or stand on the CNC machine, ask a TA for guidance on how to safely clean up around the machine.
   2. In extreme cases, it may be necessary to clean during the milling process if large amounts of material are cut away and the dust collection is not sufficient in removing the material. In this case, pause the machine or wait until the current operation has completed and the machine is in an idle state before trying to vacuum the milled surface. Remain a safe distance away from the machine in this condition.
   3. The dust created by the milling process may be hazardous to breathe; there are masks available for your protection.
   4. A broom, dust pan, and shop vacuum is available for use.
   5. Please leave the room cleaner than you found it.