Shop Update New CNC Mill

It took all year, but I’m happy to announce I finally found a CNC Mill. Why did it take so long? In short, I’m cheap. In business, it’s better to make money than spend money, but you have to spend money to make money. I took a gamble on an older Brother machine taken out of a medical device shop. At least, that was the story. I am questioning its backstory now that I’ve got into it. I’ll go over some of the details. Let’s just say that the machine tells a different story. I had to unpack, disassemble, clean, more cleaning, and reassemble, test, test, and test. Older machines always have a story to tell.

Moving it in was pretty straightforward. I contacted my shipping broker, and he handles the heavy lifting. It cost a little more to hire a broker but it’s very much worth it. He handles the truck, rigging, insurance, tracking, and scheduling. This time I had the machine shipped to my local riggers. Again riggers cost extra but worth it in this case since the machine was too heavy for my friend’s forklift. In the past, my buddy comes over with his forklift and unloads the machine and moves it into the shop.

The shipping did take a little longer due to it having to sit at my riggers till they could schedule the install. My shipping broker had a fun time with the rigger’s facility it was stored in before I purchased it. There was no on at the facility most of the day as they were out moving equipment so scheduling it wasn’t easy. He would have it scheduled for pick up and call the day before to confirm and they would totally forget about it causing him to have to reschedule it. Having a good shipping broker is very important! My riggers brought it out, and I once again had the wall removed. This time it was much easier than the 5-axis machine we had a few years ago. The guys helped me move the wall out of the way, and this machine is much smaller than the big 5-axis machine. I had the area prepped and ready, even had the floor marked exactly where I wanted it. It was also easier since I could use my pallet jack to move it around. It’s right at the edge of what it can handle but for wiggling it into place it worked great.

Cleaning and fixing were next. I was told by the seller “everything works” and I was very hopeful. It was purchased through eBay so I had a few guarantees I could lean on if it were to come up. I had to get power to it, which again was easy since I already had services ran to that area of the shop since I had a machine there previously. I had to get the blocking out that the riggers used to secure the spindle. The 6x6 wood blocks looked like they had seen many years of service. They did the job! Looking at the machine and beginning the long checklist of tasks I got to noticing the machine looked very different from the photos. The table was pitted, surface rust, and very dirty. I did have the machine moved in an enclosed trailer (worth the extra $100) but it had leaves and dirt sitting on the horizontal surfaces. My assumption is that it sat outside for a period of time. It came from Southern California so not a big deal compared to northern states but humidity and dirt are not friendly to CNC machines. No matter, the cleaning must go on! I began by checking that all axes moved, homed, and sounded fine. Next, I started taking the covers off. Y-axis cover and both X-axes came off for inspection and the much-needed cleaning. There were chips packed everywhere. Good news is that under the covers there wasn’t any of that dirt, and all the critical surfaces were coated in grease. OLD grease but it wasn’t dry. This is a grease machine as opposed to the oiled machines today. Some machinists prefer grease over oil but they both have positives and negatives.

There was lots of rags and degreaser used. Fortunately, the majority of the grime wasn’t too difficult to remove, but everything was covered in 20 years of it. It was an exercise in elbow grease and yoga. Every crack, corner, lip and seam was packed with tiny needle-like chips. It’s a BT30 machine and not meant to cut big parts. Someone was using it as it was intended. Diluting small parts. I didn’t find anything other than steel chips. No carbon, plastics, acrylics or abrasive materials that can often lead to a short machine life. I had some old coolant I had stored in a barrel I found to be very useful. I filled up the coolant pan and was able to test it as well. I used some fine filter media in the chip pan and just ran the coolant while scrubbing. Washing away the grime, and the worst of it would get caught by the filter. When everything was clean, I just sucked out all the old coolant along with the old grime. The coolant changed color from a cool blue to a deep brown from all the grime! I did flush everything with clean water to get the rest of the residue left over.

I found that the machine uses a different strategy for coolant on/off M08/M09. The pump is to be turned on by the operator but the flow is actuated by a solenoid valve that in this case was frozen in the open position. Later I was able to disassemble and clean the solenoid so it mostly works. I’ll probably be changing this out in the future. This machine has 2 coolant pumps. One for the machining coolant and one for a wash down. To my surprise, both worked even being jammed with chips and debris. The machining coolant was a little lacking, and I ended up finding an upgrade pump on eBay that has been working great. It is higher pressure and higher volume. Chips are evacuated with just the coolant pump, leaving the wash down unused for now. The chips I’m making aren’t that big for now.

Part of cleaning is to address any broken parts, worn parts, or parts that can be upgraded to make it better. Throwing tools was one of the first things I ran into. Part of my testing was doing tool changes and making sure the tool chain was working and lined up. Fortunately, I loaded an empty tool while testing. This was also before I changed the windows out. Tool changes are fast, and man am I glad I had the door closed. It launched a two-pound chunk of steel at the window, and I jumped. I was a little bummed hoping I could start loading tools and begin the real tests but I dug into it. I took off the spring-loaded holder and found the problem real quick. The springs were just gummed up and too slow to grab the tool. A little cleaning and lubricating them and they work great now. It’s more evidence that this machine was sitting for longer than I was told. If it was “working” then how was it doing tool changes? Oh well! Check that box and move on to the next.

Next was the operator panel and LCD. The skin used for the buttons was very worn and had holes in parts. To my surprise, this was able to be purchased directly from the current Brother dealer (Yamazen). The skin wasn’t all that expensive but the backlight for the LCD was another story. The skin was about $90 with shipping which is great for what you get. It’s like a large heavy-duty vinyl sticker that makes it easier to read and seals the components from coolant and dirty hands. The backlight was over $350 just for the transformer, and I couldn’t get a bulb directly from the dealer. After looking around and buying a cheap tiny CCFL that didn’t completely fix the issue I knew it had to be the transformer. No way was I going to pay $350 for a small PC board with $20 worth of components on it. I noticed that the board was being fed with a 24v power supply and that got me thinking about why not just add an LED strip and forget the rest of it. Well, that’s what I did, and it’s working great now.

Next on the long list was the door windows. The lexan was probably the original windows and were very yellowed and very scratched. So I bought a big sheet and cut it down. The gaskets used were very serviceable, and I was able to bring them back to new condition in about an hour. Since the windows weren’t broken I just used them as a template to mark the new material.

Now that we can see into the machine I got to noticing how dark it was in there. There’s a large light inside the enclosure, the light switch seems to work as I hear a relay click and the LED on the button lights up but no lights come on. It’s an old CFL and I’m sure replacing it with a factory unit would be too expensive for me. So I looked at upgrading it. I found it was fed a 200V supply. It had a ground and two lines (hot). One switched and the other didn’t. I sourced a machine light(LED) that was good for 100-250 volts and we can now see! I’m not sure what the hot wire is that just stays on. The ground is always on so it’s not a ground switching system and the other hot wire switches when you press the light button. It’s been working fine the way I have it set up.

Programming

This is where I am really getting excited! We are getting even closer to making parts. So I first checked the Fusion 360 Generic Post Processor for Brother machines, and to my surprise, most things worked. I have slowly made a few changes necessary for the older machines. I had to remove the G18/G19 moves since this machine was made before Z Radius moves. I also made some basic customization changes like changing the default parameters for writing machine info, tooling info, and number sequences. I’m drip-feeding this machine using a DNS cause it can’t handle the large G-code files of today’s strategies. I also changed its return strategy so it doesn’t take the work into the far corner when it finishes a part. It’s nice to open the door and it be as close as possible. This is easy to do using the G28 or G53 codes.

It’s really mind-blowing to see how it does its first move, tool change, preloads a tool, and calls out the WCS all in one line. I guess it has to being the machine is so fast. I was also happy to see the drilling cycles and tapping cycles work. My first project after testing accuracy was to make a fixture plate with recesses and drilled/tapped holes for work holding. It’s the coolest thing to me to see this machine drill a hole and then tap so easily. I’ve drilled/tapped a few M6 holes, and the machine doesn’t even register a load on the spindle load meter.

Today we are in production. The pry tool is on the menu! I’ve run this part 40-50 times now making some small tweaks along the way like chamfers, tolerance adjustments, and general surface finish stuff. So far I’m really impressed with this machine. I haven’t really put it to the test yet in that I’m not trying to hit a critical tolerance from a drawing. I’m machining one side so it fits in the recess I made for op two. It does this great every time. It will be a real test to see how accurate it can be when making parts that fit together. I’m pretty sure pocket clips will be next on the list. I want to make my pen as well as make clips for other gear like knives, flashlights, and pens. I’ll probably go for some knife scales eventually. I’ve already made up some drawings of some since I’ve been laser engraving them. Time will tell. If I think of something easy to make, I’ll jump on it.