Dear Friends,
It is a blustery day here in the hundred acre wood. The cold rain seems to merely deepen the exhausted frustration I feel about this bar endeavor. I'm not quite back to square one, but we are close. Frankly I would very much like to be done writing about these stupid bars. I'd like it even more if I was actually done with making them, and could move onto other things. Alas, here we are.
Last week Friday, after I had finished the letter I had a new idea. I was going to add pins to to the second operation where the long slots were. These pins would go through the holes made in operation 1, aligning the plate, and providing support in the lateral direction. I began with the drilling in earnest that morning, and promptly destroyed the fixture.
The deep pain that caused was only soothed by the fact that I was increasingly of the opinion that there was no real way to fix the issues I had been facing save starting over on a new fixture. Well I got my wish.
I spent most of the rest of that day taking some scrap and fixing the issues that had plagued the very first fixture that had been made (the one I spent all night making with Skiddy that made bars one at a time). With my revisions to the fixture and a bit of touch-up on the software, I was able to get it to make bars properly.
This solution was at best temporary, made worse by the automatic tool changer failing on Friday afternoon. Without the automatic tool changer, swapping between the spot drill, drill, tap, and endmill all had to be done manually between passes. To make bars then, the operator needed to stand in front of the machine for the full 5 minutes it took the machine to work, and had to change the tool about every minute or two. Despite this, we at least had a way to make some bars and I could get us caught back up.
Monday rolled around and I spent all that day and all of Tuesday, and most of Wednesday, manually making bars. The good news is that by Monday afternoon I had been able to repair the automatic tool changer which had been suffering from an electrical failure. The cables had vibrated loose due to the machine running and the fix was simply to pull out the plug and press the contacts back together before reinstalling. If it keeps happening, I think I am just going to replace that plug style with something better.
Once the automatic tool changer was fixed I had a bit more time while each bar was running to get some work done. Meryle and I had conferred earlier in the week about the task ahead of us, and it was clear that I needed to get the mini bar fixture made before remaking the medium bar fixture. Even though we sell far more medium bars at this point we had a way to make those bars, albeit a poor one, and we had about 3 days worth of mini bars left.
This meant I needed to design a new fixture for the mini bars. The good news is that the weekend had lead to a few hours of thinking time for me and I had come up with an ingenious solution to my problems with cutting at the center of the bars. We don't cut the center. Well technically we still do, but only in Operation 3.
This was an inspiration that came to me on Sunday night as I was falling asleep, wishing I had a good way to brace the center of the bar slots. I thought, "if only I could add a piece of metal that went across the top of the fixture at that part and I cut around it, removed it, and cut the center." This rather silly idea evolved into the much better idea I have now. For Operation 2 we will cut the top third and the bottom third of the bar, leaving the middle part of the bar solid with a solid fixture plate on top of it. That means rather than an 8.5" long slot to cut, its two roughly 2.75" slots with a support in the middle. Then in Operation 3 we cut the remaining center out which is another 2.75" slot (or about that) and the slots we cut out in Op2 have bosses (small metal parts that rise up out of the fixture to fill in the space where the lost material was) and that will much more securely hold it.
This is one of about five improvements to the design of the fixture overall.
So armed with these new ideas, I used my spare time while bars were running to actually build out the proper blueprints for the mini bar fixture plates and have a good start on the medium bar plates. That lead us to today.
I have the new material we are making the fixtures out of (1018 steel) which is both significantly heavier and thicker than the prior fixture. It also is slower to cut than 6061 aluminum. I had talked to a friend of my brothers who is a material science expert (specifically in the world of machining), and he said that 6061 aluminum is like a dense plastic in terms of its use as a fixture. This will be much better.
But, if the last fixture took me a week to get made, I will be very surprised if this one takes me less than a week, despite knowing a lot more about the fixture design. There is just a lot of waiting for the cutting to be done. Beyond that, there are some aspects of the new fixture that worry me. The new slots will be narrower and with a potentially challenging shape dimensionally. this is both a machining challenge, and also the unknown of if the slot will allow for proper cooling and chip evac. The only way to know is to make it and find out.
There is another thing nagging in the back of my mind. Skiddy awhile back had said to me that "just because somethings works for a little while, doesn't mean it will continue to work." This prompted a lot of discussion, but for the most part I had somewhat dismissed it. Of course if I could make a good fixture that worked, I could be done with doing this for a little while and could have my people run it. However the fixture I had repaired and used to make the medium bars earlier in the week brought this issue starkly into light.
I had made 40 bars in a row no problem. The machine made a low, quiet hum as it cut through the material and I was feeling good. Then at bar 41, it started to squeal when it was cutting. I replaced the tool, thinking it may have dulled. No change. I revised my work holding to ensure that the material wasn't able to move. No change. Nothing I tried seemed to make it better except dropping the RPM's down from 1800 to 1675. When I did that, the squealing stopped and it returned to its humming.
When I asked Skiddy about it he referred back to when he had mentioned the quote from above. I pressed him on this, saying that it didn't make sense why it would stop working all of the sudden. He pointed out that there are hundreds of variables that all come together with this kind of work. Machining is a clash of elemental titans. Electricity, material sciences, wear and tear, even temperature and humidity all play a part when working on these things. A change in the batch of metal, even with the same alloy composition, could throw things off. The spindle, or belt, or motor could be heating to the point where it works slightly different. A laser engraver, or the swing arm press could be pulling enough energy that the motor sees a slight dip in voltage. The coolant could have too much oil, or not enough oil in it and the lubricity and cooling could be off. Any one of these things could be causing it, or all of them could be. There is no way to really know for certain.
That worries me. A big part of how the Murdy Creative Co. has been successful is by me blazing a product path, and then figuring out how to simplify that path to allow people who are relatively untrained to be able to recreate it perfectly. If this type of work is unable to be simplified, that puts a much heavier load on us to properly train people how to diagnose and manage the issues as they might arise. If its this hard to make simple bars, it does not bode well for my long term plans for new products.
Mercifully, my whole week hasn't exclusively been relegated to the bars and fixtures. I was able to spend a little bit of time applying for a Wisconsin Economic Development grant centered around getting Wisconsin businesses to export more. Who knows if it will come through, but if it does we would have a nice sum to aggressively launch marketing in the easy over seas markets. I really want to take advantage of the new opportunity that our international shipping capability provides.
I feel like these letters are starting to sound a bit like the letters Ken Burns likes to put in his Civil War documentaries:
My Dearest Katherine,
These winter months have seemed endless. The maddening boredom of waiting for spring is only punctuated by the terror of sickness that is sweeping the camp. I long for the day when I will...
and so on and so forth. I want you to know that if you find the continued stories of machining these fixtures to be boring, just imagine how I feel actually having to do it for hours. I'm so ready for this to be done, and for me to move on to new projects. There is no shortage of them to be done.
Stay tuned for more letters on Thursdays in the coming weeks and be sure to go subscribe to our YouTube channel. If you like and watch the videos it helps us get promoted more by the algorithm to people who may never have heard of us.
Ever your servant,
Colin Murdy
CEO/Owner
Murdy Creative Co.
Cell: 414-434-9001
MurdyCreative.Co
