Machinist Apprentice | Stinaless Steel Part Programming | Day 33

Today I finished cleaning up the front of the shop and office area, then started programming the CAM for a new contract that came in the other day. 

The part is a flat plate in stainless steel with a few threaded holes and locating pins built into it. The stainless we are using is cold rolled, which means there is a lot of surface tension in the material. Just like the small stainless buttons, I worked on a couple of weeks ago, when I removed the part from the soft jaws, it sprung out at me. The same thing will happen with this plate, and so my boss instructed me how to work around it. I was to take 0.02" off of the top and bottom of the stock, then 0.05" facing step-downs evenly until I got the actual height.  By removing the small amount of material first from both sides, it would release the tension in the material and prevent it from bending later on. 

Since there are the locating features on the top face of the plate, it means the overall height of the stock has to be higher to match the highest point in the model, which requires a ton of material removal to leave just the pins. Wayne wanted me to use a parallel facing operation to cut down the material, avoiding the pins. Still, unfortunately, there isn't an option in the facing toolpath to avoid certain areas. So I played around with a few different toolpaths to see what would work best and leave an excellent surface finish. I found that the 2D pocket clearing worked the best, I was able to avoid the pins and have a decent looking path. 

The part has a unique shape, and so I'll be making and using a fixture plate for it and locating pins, which I am excited for!

Home Workspace | Multi Axis Contours | Pocket NC

First off, I want to say thank you to everyone who commented on yesterday's post with the PNC pocketing issues. I was able to solve the problem I was having by changing the operation from a 3D pocket clearing to a 2D pocket clearing. The ramp down was still the same, but it didn't take roughing step-downs and went all the way to the bottom then retracted up in one motion. 

I then started getting into some of the multi-axis portions of the CAM, which got a little complicated. The part has quite a few unique angles that require simulations 5-axis work. For all the flat, curved faces, it was pretty easy to do with a flow toolpath. However, when I got into the contouring for the pockets, I ran into some issues. Typically you would use a swarf toolpath and simply select the top and bottom 2D contours. Except this part doesn't have specifically defined line segments on the interior of the piece, and so you only have one point of contact (the outside parameter of the pocket). I'm somewhat new to simultaneous 5-axis programming; any insight would be greatly appreciated!

I am also using the Pocket NC simulator to check and see the toolpath functions as it should in Fusion360. I ran into some issues when trying to post the gcode where it would keep giving me errors "<post name>.failed", until I figured out it was with the 5-axis flow toolpath, I narrowed it down to the maximum tilt the machine would allow and lowered it from 180deg to 15deg.

Machinist Apprentice | Deeper Cleaning | Day 32

Today I spent the entire day at the shop scrubbing the floors to get them to shine!

I was initially tasked with finishing the corner of the shop, where I didn't have time to do a few weeks ago. Still, after doing that with some heavier cleaning supplies (scotch bright and degreaser), it looked too clean compared to the area around it, and so went through and cleaned the rest of the floors. There is quite a contrast with the before and after, and I thought what I did a few weeks ago was good, it was nowhere near what it was today. 

The downside to using the scotch bright is it removes the seal on the floor but was already scratched up so bad it didn't make a huge difference. My boss is going to have me redo all the floors by sanding, polishing, and sealing when the shop gets slow. 

Wayne also got another contract, which I'll be working on tomorrow. It's a large 7"x3"x1/2" plate in stainless with some unusual geometry to work around. 

Home Workspace | Ramping Issues on a New Part | Pocket NC

I'm trying something a bit different from the Pocket NC since I have limited time, and that is to restrict it even further by only allowing myself 30 minutes each day, which will give me time to think about it more and ask the community. 

This part is the first of a set that I am teaming up with @jaelen_hsu to make. I'm using the er40 fixture setup on the PNC with a 1" round aluminum stock. It's got quite a few interesting angles and is going to be a challenge, which I am very excited about!

While programming it (started with adaptive clearing to remove the bulk of the material), I did a pocketing operation with a 1/8" endmill to clean out those holes. However, I noticed that the ramping on it was quite long, and once it reached it's pre-defined stepdown, it would retract and do it all over again. I recorded a short video showing what's happening, and I haven't had a huge amount of time to play around with it. But I do know it's not directly related to the ramping section in the linking tab. If anyone has any insight on this issue or a better way to clear out those pockets, let me know!

Machinist Apprentice | Aluminum Threadmilling Troubles | Day 31

Today I was able to finish up making the parts I started earlier this week and get those deburred and cleaned up. I noticed a small mark on the wall of the part which was where the endmill lead out of the contouring toolpath. I should have had it lead out along the line of the wall instead of coming at a 90deg angle horizontally. I was thankfully able to get it cleaned up pretty easily with a light sanding.

These pieces have a couple of holes on them that needed 2m-0.4 threads, which I wrote about having some CAM issues last week, which I solved on the software end of it. However, when I went to go and mill out the threads, I found that they where much too tight, which I kind of figured might happen. I talked to my boss about it, and he suggested creeping up on the thread size by increasing the tip diameter offset one thou at a time. Which I did for about four thou and still nothing, I didn't go higher than this because when I simulated the highest offset value I put, the tool was almost rubbing against the walls of the 1/16" hole. I'm honestly not sure why the thread milling wasn't working and ran out of time to play around with it and had to thread them by hand. 

If anyone has an idea what the reason could be, I'd be much appreciated! Tomorrow I'll spend a few hours on the thread milling and tap drilling with some scrap pieces of aluminum. 

I also had some weird issues with the laptop my boss picked up to work on. The screen would flicker quite a bit, and after googling the problem and updating the windows software, it would get worse! It mostly occurred when running Fusion360 and having a few tabs going taking up a lot of the CPU, and would get to the point where I could only see the screen every couple seconds due to the noise. I called up Dell customer support to see if they had any ideas, but there was quite a bit of confusion over the phone and could hardly understand what they were saying, so I decided just to spend a bit more time researching the issue. After trying a dozen different things, I finally found something that fixed the problem, at least for now. Under the device manager, I deleted the graphics card and rebooted the computer. I then updated windows to get the backup file of the graphics card, and that worked!