CNC Lathe project-Center Punch

This is my extrusion for my slots.

For my lathe project I decided to design a Center Punch. At first I was only going to make one part of the center punch until I was told I could make both parts as long as they're no longer than 3in. For my first part, the point, I created a sketch in Fusion 360 and designed a couple boxes no wider than .9in since our stock was only 1in wide, (stock is the material we put in the machine to cut the part out of.) After my boxes were done I revolved them around the center axis to make them round and symmetrical. Next I moved on to designing the slots on the side of the back part of the point, I did these for design purposes, I thought the part looked nicer and was a little more complex with them. For the slots I used a tangent plane to select the side I wanted the first slot on, created a sketch on that plane, and sketched a box that is L0.70in by W0.232in, after I had the sketch of the box I extruded it in by -0.05in then repeated this process on the other side.

Once those were finished I moved on to designing my screw hole in one of the slots, the point of it would be to put a screw in it to keep it from sliding out of the second part once inserted. It took me a while to get the thread designed because the thread tool didn't work when I drew a circle outline in my sketch, instead I had to use the hole feature to get the thread working. Once I was able to use the thread tool I had to figure out what size thread would work best, I ended up having to go pretty small because of my part parameters. I made the threads 0.25inches in size and 1/4-20 UNC in designation, and I used thread type ANSI Unified Screw Threads.

After making the threads I moved on to making a detailed blueprint for this part, I finished the blueprint pretty quickly because my first part (my point) doesn't have much to show in a blueprint.

This is my thread.

This is my center bore. A center bore is when the tool cuts a hole in the direct center of the part.

This is my center bore extrusion.

After making my first blueprint I moved onto designing my second part, the holder. First I created a sketch and made boxes like I did with the point, no bigger than .9in and revolved the sketch around the center axis. I then created a plane on the back side of the part to design my center bore. On that plane I created a sketch to design a circle that has a .404 diameter, after creating this I extruded it into my part 1.90 in. After finishing that extrusion I created a tangent plane on the side of the part to make a slot hole with a diameter of .399in into the center of the holder to give the screw from the point something to collide with to keep the point inside. Once I finished that I made my blueprint for the holder.

This is the holder slot sketch.

This is my slot extrusion.

This is the "Face Cut".

Point face cut.mp4

This is the "Rough Turning" pass.

Point rough turning.mp4

This is the "Part Off".

Point part off.mp4

Now I started CAM-ing the parts. CAM is when you replicate what would happen when you cut the parts on the machine in Fusion 360. The CAM process is what takes the longest because it's all about precision and details, you have to have the right tool size, the right angle for the tool to cut, the right heights and clearances, and even with these things you can still get errors. The first thing I did when CAM-ing my part was my setup, I had the chuck positioned at the back of my part with a little bit of distance behind since I had extra stock so I could have clearance which made it easier to do the part off at the end of the program.

For my first OP 1.1 I faced the part with tool 2 (T2) (1/2 turning tool) facing the part is important to ensure a flat cutting surface. I used T2 for this because I thought it made the most sense to use. OP 1.2 is a rough turning pass using T4 a 1/2in turning tool, rough turning helps shape the part to the desired shape and cuts a lot of material fast. OP 1.3 is a grooving rough turning with T6 a 0.1155in turning grooving tool, I used this tool pass to get the point to look like how I wanted it to since the rough turning didn't do everything. OP 1.4 is a pocket cut for my slots cut with T1 a 1/8 flat endmill. OP 1.5 is the making of the thread cut with T5 a 0.15 in thread mill. OP 1.6 is my part off done by T8 a turning grooving tool.

This is the "Grooving Rough Turning" pass.

Point grooving rough turning.mp4

This is the "Pocket Cut".

Point slot cuts.mp4

This is the "Thread Cut".

Point thread cut.mp4

This is the "Face Cut".

Holder face cut.mp4

This is the "Profile Roughing".

Holder profile roughing.mp4

This is the "Part Off".

Holder part off.mp4

Now I started CAM-ing the holder. The first thing I did was my setup, I had the chuck positioned at the back of the holder with a little bit of distance behind since I had extra stock so I could have clearance which made it easier to do the part off at the end of the program.

For my first operation (2.1) I faced my part with T2 a 1/2 in turning tool which is when the cutter comes down and cuts a little bit of the face of the part off to give it a cleaner look. OP 2.2 is a profile roughing with T4 (1/2 in turning tool), the profile roughing cleans the part up and makes it look shinier and more appealing. OP 2.3 is a profile finishing done with T6 a turning grooving tool, this pass is used to get the part down to the desired size and surface finish. OP 2.4 is my center bore cut with T12 a 0.3937 in drill, this OP is used to make the hole to fit the point inside of the holder. OP 2.5 is my slot cut with T1 a 0.1in flat end mill, this cut is important for keeping the point inside the holder because the screw from the point is going to stick out and collide with the slot. OP 2.5 is the final OP of the holder is my part off done by T1, this is the cut that cuts my part off from the stock which is why it's the last OP.

This is the "Profile Finishing".

Holder profile finishing.mp4

This is the "Center Bore".

Holder center bore.mp4

This is the "Slot Cut".

Holder slot cut.mp4

Now I got my g-code approved and started cutting my the point part of the center punch. We first ran a simulation on the pendant and then did a dry run, a dry run is where there's no stock for the tools to cut but you run the program anyway to be sure the offsets are set correctly. After my dry run was completed I began running my first part on the lathe. I stood by the lathe the whole time with my finger on the feed hold button to stop the machine if something went wrong. On my first run of my part the endmill didn't cut the pockets but I kept it running to see if there were any other flaws in the program, there weren't any other flaws but I didn't like how small the point was so I went back into fusion and designed it two inches bigger than it was. I've inserted visuals of each step of the process of cutting the first "Point" below.

Before making my second "Point" I went into Fusion 360 and adjusted a few things, I adjusted the heights on the pocket cut lower to ensure the cutter would make those cuts this time. I also made it two inches bigger because I felt that 1.5IN was too small.

After making my adjustments in fusion I exported the G-code onto a thumb drive, inserted the new code into the machine and started it. We didn't do a dry run this time because we had already proved out the program. The second run went great, all the cuts were made where they were programmed and it looked a lot better.

Profile finishing

Pocket cut

Other pocket cut

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