Parts of a Mill
Setting up a Mill
Setting up a mill is a simple process. It is slightly different on the mill and the lathe, but it is very similar, with similar steps. If you do not set up your mill correctly, you will not have a good part.
Setting up a Part in the Mill
Setting up a mill is not very complicated. You start first by setting up your work piece, which will often be in a vise. You need to select a pair of parellels. Parellels go into the vise to help lift up your stock, to avoid hitting the jaws of the vise when machining. after selecting parallels, you need to set up a stop. This are located in the drill chuck drawer. This will be attached on the back jaw, and tightened with an allen wrench. The stop helps to keep your part zero, so that you can quickly make more then one part acuratly. After you put on the stop you go through the process of zeroing
Collets
Collets are how the mill holds straight shank tools in the spindle. To do this select the collet you want, and put it into the quill. First tighten the rod on the top of the mill by hand (while holding the collet in place), insert the tool, and then tighten further with the wrench. Make sure that you press the brake when tightening with the wrench so that you are actually tightening the collet. If you do not press the brake, the collet will spin. Think of it like a nut on a bolt, you have to hold the nut still to thread the nut up the bolt. To remove the collet,first loosen the collet with the wrench (while pressing the break), only use the wrench untill the collet is lose by about one full turn. Grab the endmill with a paper towel before proceding to the next step. After grabing the endmill lightly, hit the rod with a dead-blow hammer or brass hammer on the back of the wrench. This will drop the end mill out. After the endmill is removed, put your hand under the collet while you continue to loosen the rod. The collet will eventually fall out.
Finding the refrence zero on a mill
To zero is to percisly locate a corner of the part as shown on the working drawing. It can also be refered to as the origin, like in the coordinate system. To do this you first have to put a drill chuck in the mill. After the drill chuck is tight in the spindle, you have to insert an edge finder into the chuck. The edge finder should be run at roughly 1000 rpm. NEVER ADJUST RPM WITHOUT THE MACHINE RUNNING After you tighen the chuck, you slowly approach either your x or y edge of the stop. You should always zero on the back of the vise, because it does not move. Slowly approach the edge with the edgefinder. The bottom cylinder of the edgefinder needs to be able to touch the edge you are referencing. Slowly turn the handle untill the edgefinder kicks out to one side. After the edge finder kicks out, you can press the zero button on the digital readout (DRO) for whatever axis you are referencing, raise the quill, and turn off the machine. Your next step is to move the table the radius of your edgefinder. The zero you just set will be off by the radius of your edge finder, so you must move the table the radius of the edgefinder, and then press the zero button on the coorsponding axis on the DRO again. Check to make sure you moved the right direction, by bringing down the quill, and seeing if the center is on your referenced edge. If it is not, you went the wrong direction and need to move and press the zero button.
Drilling a hole
After you zero your machine, you can take out the edgefinder, and put in a spot drill. We spot drill holes to avoid the drill wandering, and making inacurate holes. After the spot drill is in, insert your part. To do this you will put the part on top of the parallels, and snugly agaisnt the stop. You should use a deadblow hammer after tightening the vise to make sure that the part is firmly in the vise. You should next move the table to the position of your first hole. To spot drill your whole, you slowly bring down the quill onto the part. The spot drill does not need to go in all the way, only make a small hole for the drill to center on. After all holes are spot drilled, you then put in your drill bit. Adjust the RPM according to the size drill you are using. Put cutting oil on the hole location, and on the drill. Next bring down the quil in a slow pecking motion to break the chip and drill the hole.
Facing set up
After your stop is set, you might need to cut your stock down to an exact size. To do this you first have to put an endmill into the Mill. You have to grab an endmill from the mill tooling drawer, and pick the correct size collet. To pick an endmill, make sure that you take into consideration the thickness of your part. The endmill should be slightly longer then the thickness of the part, so that you can make it in one cut. Insert the collet and endmill and tighten it. Remember, because our zero is at the center of the endmill, you need to add the radius of the endmill when making a cut. Make sure that the stock if firmly agaist the stop, and hit it with a deadblow hammer to insure that the part is flat.
Facing
The process of facing can be slightly complicated. To face the edge of a part, make sure that the edge is sticking out the end of the vise. You will then move the quill down so that the endmill can take the entire edge with one cut. Depending on what material you are cutting you will want to adjust the RPM. Next you will start the machine, and move the end mill so that you are taking off just a little. You will barely touch the part and press the zero button. This will make sure that you can acuratly take material off to get to the right size. You will want to measure your part to take off the right, and are within tolerance.