Day One-CNC Basics (10/30/24)

 Today we went onto the shop floor to learn about CNC 3 axis machines. First make sure you check your area and clean if needed, and make sure you check your coolant to make sure it is plugged in and won't just go every where when you turn on the machine. Then we learned that when you turn off the machine when ever you turn it back on you should run the warm-up program in memory. 

The MDI (Manual Data Input) is used for many things but we used it to switch to different tools. We used MDI and typed in M6 T2 (M6 is used to switch out the tool you have in at the moment for another one in your CNC machine, and T2 is just telling the CNC machine that you want tool two) for and example to switch the tool from whatever was in to tool 2 Also, instead you could press the MDI button click T and the tool number you want to switch out and then press the ATC button. Also you would use MDI to lock and unlock the Spindle, the way you would is you click MDI and type in M19 (Orient Spindle) and enter to lock your spindle. 

Every time start a new work order you need to physically take out the tool and check to make sure it is the tool it says it is in the tool list. The way you do this is first you need to hold pretty high up on the tool and hold the black button until the tool falls out. Also to put the tool back into the machine you hold the tool up and make sure you line up the tabs and hold the black button until the the machine vacuums the tool into place. Now you can check your tool, our mentor had the tool list for their part already printed out, we just checked tool 2 because he had already checked them all and he didn't want to waste time. The way we check the tool is on the tool sheet for tool 2 in tool description is shows 0.50 diameter, 1.25 LOC (Length of cut) the length from the face of the mill/flutes the the base of the flutes, and 1.75 OOH (out of holder) how much the tool is out of the holder from the base to the holder. We then checked the tool to see if it matched the tool sheet. Also, we had to check the Haimer to see if the tool fit snug in it. 

Also, we learned how to find your program and how to copy it onto the memory of your CNC machine. Firstly you should check to see if our user data has been cleared, and if not you should clear it with F1 just so you don't get confused when picking your program. Now you want to go on your computer off to the side of the machine and open predator PDM. Now in the find search bar type in your program name tell it highlights it in blue under the find bar, and double click on the highlighted blue program. You will find the program, how to set up your part in the machine, and if there are multiple runs of the same part (set up and multiple runs explained more in next paragraph). The way to send it to the machine panel is so right click on the program that ends with NC and then click send to CNC. Now when you go into List programs and into the user data tab you should see your program, and now if you click F2 it will bring up a copy to page, click memory and enter. In the memory tab of the list program button there should be your program. Now if you click the memory button you will see your program ready to go. 

your program will show you how to set up your part, how many different runs you need to do on the one part, and where to zero your axis. As an example on this part for the first run it wants you to zero your axis on the leftmost side. It also shows how to load your part on the vises. 

This program says that you need these clamps on certain holes on this giant vise to hold the part, you had to use a drill to take these off and place them on the correct holes. 

Day Two-Tools and tool holding (10/31/2024)

We saw three different tools and their different cuts. First was a 0.625 square end rougher mill we used both the face and side of the end mill for our cuts. Then it was a 2.0 face mill this was used to face one side of the part so it is flat and every other tool used on that side will now have a flat surface to start on. Lastly was a 0.375 ball nose end mill the ball mill is mainly used for external radius cuts. The tools we used were numbers 10, 1, and 8 on the tool list. 

On the tool list used for making the part tool number 10, 16, 14, and 15 were all pulled and put into a shrink-fit holder, while tool numbers 11, 2, 1, 8, 9, 6, and 4 were standard tools that were already in the machine's tool list. 

Every time you start a part you should check all the tool you will be using to cut out your part. on your part list you you will see your tool description this has all the dimensions you will need to make sure your tool is good you use. 0.625 is the diameter you need to make sure that it close to 0.625 of an inch as possible you would use calipers to mesure. 5FLT is the number of flutes in your mill you would just count the flutes. 0.030R is the radius of your flutes at the face of your mill, so you would use your radius gages to check. 1.875 is your length of cut/how long it is from the base of your flutes to the face of your mill calipers would be used. 2.50 OOH is your out of holder length/how far the mill is out of the holder either collet or shrink, measure using calipers. 

This is a collet holder we had a fake tool number made so we could practice, this tool needed a 0.25 thou stub drill (there are different types of drills, stub and jobbers stubs are short drills while jobbers are long drills) with an 1.5 out of holder measurement and a 32 collet holder. So, we went to tool storage found an 1/4 drill measured just to make sure and then measured out 1.5 on a caliper and held them from the face of the mill and marked that on the drill, then we found our collet holder. We then unscrewed the holder and flipped the top of it upside down and placed the collet in the top of the holder, and then we screwed the bottom part of the holder on just tight enough so it doesn't fall out of place. Now we place the holder with the collet into the tool holder and place our drill into the collet, then tighten with the collet chuck wrench.

The first thing we did was find our end mill, the way we did this is we went into the tool storage and into the 1/2 drawer. Then we searched for straight edge end mill because the tool description called for a radius of 0. Now we want to measure the diameter and LOC, and mark the OOH (I explained what we did for these in the collet paragraph).  Now what you want to do for a shrink holder is set your settings / your conversions (we had a 1/2 so 10mm to 12mm) there is a dial at the top of the shrink fit machine that you can move to  10-12 mm. Have vise grips/pliers ready to grab your tool at the marked line we did for the OOH, pull down the heater part of the shrink fit machine down and hold the button until  the timer is up then release the heater and bring it back up so its not in your way, grab your tool with your pliers and hold it in the holder and twist until the holder moves with the tool, now put on the correct cooler (10-12 mm). 

Day Three-Offsets (11/1/2024)

Probing is what i learned today, to start off with we had to switch tools to the prob tool. we did this by going to MDI and typing T25 (which is the tool number the prob was on) and then pressing ATC. 

Now that we have our prob tool selected we can go to the set up document to find what G-code we want our coordinate to be based off of and how to zero our x, y, and z. We started off with zeroing the X, the program wants us to use the prob in a hole on the right side. Firstly we measured the hole for later, and then we brought the prob all the way down and into the hole. Now we want to click MDI then program convers button to bring up the green and black screen. With this screen you want to use the cursor and press enter on the top left corner / the hole diameter. Once in this screen you need to enter information in (the hole diameter and the G code that the program wants the X zero for use is was G59) Once the information is in you then press the enter button. Now it will ask where you want this info to go (we brought it to MDI), now press MDI and press the green start button and the machine will use the prob. Now when you press offset you will see that the x-axis has an offset. 

Next we zeroed our Y to do this firstly we had to rotate the piece so we could probe a flat surface. To rotate it we had to input a short g-code into MDI, this code was G00 (Rapid motion) G90 (Absolute Position Command) G59 (Offset Coordinate System) A90 (rotate a-axis by 90 degrees from 0). Now we just have to go into MDI to Program covers pick probe y plus surface, enter the work offset (59) send to MDI, click MDI and then press the start button. Now if you go into your offset page it will be inserted into G59. 

Lastly for probing we zeroed out the Z axis, to do this we put a 2 4 6 block (a 2'' by 4'' by 6'' block) in front of the Echnigrip (so that the top of the block is at the middle of it). Now you press the same buttons of MDI, Program convers, Spindle Probe 1-9, z axis (middle right box), enter your offset number (59), send to MDI, MDI, Start button. The probe will scan your z axis and insert it into your offset page. 

Day Four-Maintenance (11/03/24)

Cleaning up your chips is a daily maintenance you should be doing. To clean them up you just need to turn on your Chip auger with the chip FWD button, and now you grab a broom and push all these piles into the auger. You can use the coolant spray to get the walls and chips that you can't easily get with the broom, but first you need to turn off the coolant that sprays at the cutting tool by turning the black lever above the cutting tool towards you (so you don't get sprayed while using the coolant spray.

You also need to make sure you clean the inside of the spindle so that it has a good tight grip on the tools. you can do this by using the tool for it with a rag over it. Also you should use a rag on the actual tool where the spindle holds on to the tool. 

You should clean the tool changer as well. The way to do this is by setting the machine to a low speed and changing an empty tool with another empty tool, and when the arm is as low as it will go you press the e-stop button. This way the machine will stop and you can easily clean the tool changer arm. Make sure that you check the nipples of the arm to see if they need to have more lube applied. 

Make sure you check the back of your machine for your air pressure, your oil levels, and check the wiring in the back for chips and if there is a lot then you should clean it out with a shop vac. Your air pressure should be between 80 and 120, and your oil levels should be between 450 and 550 and in-between the min and max lines. 

Cleaning the top and sides of your machine is important so that all the grime and lubricant is off of the machine, we did this with a cleaner spray and rags. 

It is very important to check your coolant levels, to do this you need a refractometer with this tool you need to get a little coolant on it blue bit on the end and close the glass top onto it. Now look into the refractometer and you will see a scale with a distinct line between white and blue for us that landed on 2 so we could just add some Cimcool (a coolant cleaner) or we could just replace the coolant with new coolant. 

Fully replacing the coolant is important to not miss anything because you want to make sure that this coolant last a long time. You start with taking out the pump that's in the coolant, bring over your barrel that will suck up the old coolant. When you are sucking up the old coolant make sure that the hose isn't fulling submerged in the coolant because if it is is it could back up and shoot out the hose. Once most of the old coolant is out you will now have a lot of metal mush, you need to cut up this mush (we used a metal shovel thing). Now that the mush is cut up you can use a shop vac to suck up the metal mush. After all the mush is cleaned up you should use more cleaner and rags to clean up the sides, tops, and bottoms of the parts. After everything is clean you can place all of the parts back together, and now you can fill it up with new coolant. 

CNC 3-Axis Challenge 

We had to design a part that had at least one blind hole (hole that doesn't go though the whole part), one thru-hole (hole that goes though the part), one step in height, and it had to be within a stock of 6in by 3.5in by 2.5in. Then we get to make the actual part with a 3-axis CNC machine with aluminum. When the part was finished we get 0.010 tolerance to the part made in fusion. We can only use the standard tool list that the skills CNC machines have. I used T10 (3/4" rougher end mill), T4 (1/4" SC end mill), T8 (3/8" ball-nose end mill), T12 (1/2" 45 degree chamfer mill). 

 This is the part I designed and simulated, in the design tab of fusion I made this part. I made sure that there was a step in z, at least one though hole, and at least one blind hole. The step in z is the slope down, there are three though holes they are the holes in the pockets on the left side of the part, and the blind hole is the hole in the slope on the right side. The whole part fits within the 6" by  3.5" by 2.5" stock we were given. Then I went into the manufacture tab and made a setup for my part, in this setup I made the stock to cut from. Next I made my first tool path witch was the 3/4th straight edge end mill this path cut a rough look of my part. I then made another toolpath, this one was the 1/4th straight edge end mill and it cut three holes and two pockets. The third path was with the 3/8th ball nose end mill then smoothed out my  slope/my step in z. Lastly I used the 1/2 45 degree chamfer tool to make the fourth toolpath, this path cut a chamfer to the edge of my holes and part. One problem that I had was my part was at the bottom of the stock in fusion (which means that I would have to cut down to the bottom of the stock) That would waste a lot of time and material when instead I could just move my part to the top of the stock, so I wouldn't waste time machining all the way down. 

11/25/24: Today I went down to the floor to machine my part that I made. I went down with the mentor that checked my g-code to make sure it looked good. We took all the offsets off of the back right of my part like how you should when machining. Unfortunately though the g-code was acting like it was starting from the front left of my part. This was because in fusion even though I had it start in the right back the origin was in the front left, and it was acting like that was where I wanted to start but it wasn't. So we just took the offsets off of the front left of the block and everything went perfectly. After we took the offsets we started the g-code at a slow pace so if anything went wrong we could stop it fast. Even though it was slow every tool cut how it did in the simulation on fusion 360. I paused the the code in-between toolpaths to take pictures.

11/26/24: Tuesday I went and got my part checked by a mentor in inspection. Unfortunately the whole outside of my part was about 40 thou bigger than it should of been and all of the holes were about 0.040" smaller than it should have been, but the heights of everything and the deepness's of all the holes were correct. I figured out that the problem was in fusion 360 where on my first two cuts (the 3/4th endmill and the 1/4th endmill) had the option "stock to leave" checked on which made it so that there was an extra 20 thou on each side and on the insides of my part. Now I have learned that I should check that off next time I make a program in fusion.