I hadn’t paid much attention to Haas Automation until recently. When I took my machining classes, there were no Haas machines in the school shop. My awareness of the company did not extend very far beyond the fact a Haas machine is on the cover of my textbook.
That changed recently because Tux-Lab is a fan of Haas Automation. The machine tools (which I aspire to operate) are all Haas machines. I started learning about them and the more I learned, the more I liked what I saw.
First, they are the Home Team. Based in Oxnard, CA, roughly two hours drive away from where I currently live. It is challenging to operate a manufacturing business in the USA, never mind Southern California, and I’m happy to see they’ve found some measure of success in the face of overseas competition.
Second, they have transparent pricing of their equipment listed on a web configuration tool. No “contact your sales representative for a quote” runaround. I’m sure large customers can (and do) negotiate a discount, but at least there’s a price up there on the screen to let people know what they should expect.
The third and most important thing that impressed me: they are friendly to customers who wish to work on their own machines. Sure, they have the standard disclaimer “[work] should be done by authorized trained personnel” but they publish a lot of useful reference information for those who wish to forge ahead anyway. Most other machine tool companies do not publish this information. These non-DIY-friendly companies tell their customers to “contact your authorized service representative.”
And lastly – Haas open their doors to customers (and potential customers) during HaasTec, their own open-house event. See the factory in action, see Haas machines building more Haas machines. That sounds like a Disneyland trip for machining geeks, sign me up!
Many years ago I developed an interest in machining so I could tackle projects that demand capability beyond pliers and a Dremel tool. I found evening classes offered by Lake Washington Institute of Technology (formerly Lake Washington Technical College). The campus is only a short drive from where I lived at the time. I enrolled in the Machining Technology program on the theory I could learn by attending classes on my way home after work.
In reality I only managed two quarters of classes before my full-time job demands picked up so much I could no longer keep up the night classes. Since I’m unlikely to stock my own home workshop with industrial-level machine tools, I wrote the whole thing off as a self-enrichment learning exercise with no practical application. Or I almost did, because I kept my textbooks on the chance I would need them again.
That was a good thing, because another opportunity has now presented itself. There are a few machine tools at Tux Lab which gives me motivation. If I can get myself up to speed again and prove I’m not likely to break the machines, I might be able to return to those ideas that needed more than a Dremel tool. (And in the years since, I would add “… or a 3D printer.”)
So I dusted off my many-years-old textbook and started reviewing the fundamentals because I believed the fundamentals of machining has not changed. Computer software has evolved tremendously in this time but metal is metal. Still, I was curious about the current status of the book so I looked it up on Amazon.com. My textbook is Machining and CNC Technology (First Edition) by Michael Fitzpatrick. It’s currently going for about $20, which I’m sure is far less than what I had paid.
According to Amazon, a second edition (~$40) has come and gone and we’re now on the third edition. And because it is the latest and specified by college instructors, the price is over $200. Ten times the first edition, and five times the second edition. Ouch!
Even in the age of Amazon, the college textbook market is still very distorted.
Now that we have a baseline on the vacuum table performance, time to start performing modifications to see what happens.
The easiest thing to reduce air resistance is to remove layers – we don’t strictly need the spoilboard in this setup, so it is removed. We then added some rubber gaskets to improve the seal between the plenum and the fixture, which should reduce air leaking past that particular junction.
These modifications did not drop the vacuum of an empty fixture – in fact vacuum was boosted by 2 inches to 25. This implied having the spoilboard in the setup was letting a lot of air slip around the fixture. Removing it was a good call.
When the work pieces are in place, the vacuum went up another inch to 26 inches. Less air is leaking past the work pieces, and they are now held by about one inch of mercury (roughly half a pound per square inch.)
We haven’t put any effort into improving the sealing between the work pieces and the fixture. How much gain can we realistically expect from the effort? In order to get a rough estimate of how much more we might gain, we draped a plastic sheet over the fixture.
Looks like we have about 1.5 inches of mercury we can gain from better workpiece-to-fixture sealing.
This is a promising start, as this tells us we’re in reach of a decently high level of vacuum for work-holding. We now need to put some effort into the other side – improve the path for the vacuum to reach the work pieces and hold them in place.
The CNC router at Tux-Lab has been under-utilized partly due to its under-performing vacuum table. It has a poor track record on an existing project, and we want to understand why (and hopefully fix the problem) before doing more projects on the CNC router.
To narrow down the cause, we will record the pump’s vacuum gauge reading at various configurations. We use a phone to take a picture identifying the vacuum configuration. We then hold that picture up next to the gauge and take a picture of the phone and the gauge together.
Establish the bounds
First, we get the upper bound: once the pump is up and running, close all the zone valves. The reading – nearly 30 inches of mercury – confirms the pump itself and the majority of the vacuum piping is in good working order.
The lower bound is obtained by opening all zone valves and place nothing on the spoilboard. When in working configuration, the vacuum will never be weaker than this 7.5 inch reading.
Most of the tests confirmed that the vacuum setup itself appears to be in good working order. We only started seeing problematic numbers once we started involving the spoilboard and the project fixture. Good news since these are the easiest pieces to fix.
Past runs of the existing project has been done with the fixture mounted on the spoilboard. The vacuum reading of this configuration is surprisingly high at a hair under 23 inches. Indicating a lot of air resistance despite being carved from low density fiberboard.
We then added the work piece blanks on top of the fixture and measured again.
The vacuum barely changed, to just a hair over 23 inches. This is a problem: it tells us the air can easily find a path around the work pieces so very little of atmospheric pressure is applied to hold pieces in place.
Now the objective is to modify the setup to (1) reduce the vacuum reading of an empty fixture and also (2) increase the vacuum reading of the populated fixture.
Increasing difference between these two readings should increase the holding power.