January 2020 Machine Shop Meeting 1-25-20

Machine Shop
#1

So its getting close to that time again. Time for another Machine Shop Committee Meeting.

As usual it is 5pm in the Lecture Hall.

We will discuss the past month in review. Any issues that have come up.

Consumables, What we need to replace.

Future items we would like to see.

We will be discussing the Aluminum Cold saw issues. We recently had a kickback that shows we need to discuss our procedure & policy on it. That could be better fixturing, minimum length for cutting. Whatever good solution we can come up with.

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#2

A reminder from the 10-27-18 committee meeting minutes:
CNC Lathe Will be finished by January of 2019 or it will be given back to the donor with all of the parts that DMS bought for it. Vote All for, No Opposed.

So for the meeting agenda we need to re-add this discussion. Where are we with it? People said they would work on it after the last meeting. Did they? what is our total invenstment/loss on this after 1 year? This has already been voted on to return it and is now a year overdue. And that is after it sat for a year before we decided to go in a different direction with it with a new controller. So don’t renege on our word like the BoD did. I know this is up to volunteers but if it never finished it is just a waste of effort and money.
This is also why I was never in favor of group projects. They never finish. Lots of volunteers up front, turned into two people, now less, now some people saying they’ll do it and well, you can see where we are.
Warmest regards.

----addendum----
I realize this was a generous donation from Rich Meyer. If Rich does not want it back, I would move that it be sold.

#3

You wanna explain this?

#4

no
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#5

Then stop throwing vague stones. Nobody appreciates it.

#6

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#7

Try again, while you may not appreciate it, we do in fact keep the space running. Your continued denigration of the people who make this place work is tiring at best.

Further, I’m not sure what you are on about, so why not come out and tell everyone instead of just constantly sniping.

#8

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#9

Is replacing both cold saws with a horizontal bandsaw w/ auto downfeed on the table?

#10

Band saws cannot compete with how the Kalamazoo type Cold Cut saw cut. Not on speed, cleanliness/flatness/surface finish of cut, or repeatability of angles.

We also have a “new to DMS” horizontal band saw awaiting space to be be used.

#11

I have suggested we try to acquire one of these. the user cannot pull on it to try to make it go faster, or push into it. We cut multiple hundreds of steel and aluminum parts with this before having to change the blade. Even with worn teeth it does a friction cut but at a controlled rate. However, this would only be a solution for the problems with the horizontal and vertical bandsaws. The Cold Saw is invaluable.

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#12

If the CNC Sherline Lathe is no longer needed at DMS I will gladly take it back. The only tooling that came with it was a 3-Jaw Chuck. I could use it to make a miniature camshaft grinder or just spare parts for my other Sherline CNC Mill and CNC Lathe that I have at home. Sherlines are great metal working machines that can do everything the HAAS and Bridgeport can do, just on a smaller scale.

At the moment DMS Expansion work is taking 100% of my time otherwise I would work on it.

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#13

Interesting, in all the shops I’ve been in and the tours of others posted online the overwhelming majority use bandsaws. If it were hands down the better option I would’ve expected it to be more popular.

The vertical saw with a moving blade seems to be what everyone wants, but is out of the price range or unavailable to most.

#14

I didn’t say band saws weren’t useful or anything about replacing existing bandsaws. I was replying to this:
Is replacing both cold saws with a horizontal bandsaw w/ auto downfeed on the table?

Cold Cut (CCS), Vertical Band Saw (VBS) and Horizontal Band Saw (HBS) all have strengths and weaknesses.

Companies that do a lot of heavy cutting, especially of heavier thicker material, use CCS type saws, they fast, have excellent blade life, and the coolant flooding keeps the blade lubricated and cool as well as the material. Large high speed band saws also use coolant flooding.

You really can’t compare the time it takes to cut material on a VBS/HBS vs CCS. Band saws have advantages over cold cut saws and vice versa.

  • Band saws can cut THICKER materials, theoretically limited to the gap between table and how high the blade will go. (as a practical matter probably about 4" if a solid bar stock on how sized machines)
  • VBS’s are limited to the throat depth for how LONG the two pieces can be.
  • CCS and HBS saws can cut any length of material up to max thickness limited only by space on either side of the vise. E.g. CCS/VBS can cut a 4" piece of solid bar stock 20’ in half, 10" on either side, a VBS can cut a 20’ piece into two pieces but one piece limited to throat depth - say 24"
  • VBS can cut curves, HBS and CC cannot. Material size is pretty much limited to what you can hold. VBS typically do not have out feed roller tables.

DMS is fortunate that we have all three. I’ve cut steel blanks for classes. It took about 90 minutes to cut 8 pieces on the HBS, about about 15 minutes on the CCS. With a better cut finish.

#15

I worked on the sherline Thursday afternoon/evening.I worked on it for about 5-6 hours trying to resolve an issue. I kept getting a g-code error of “Radius to end of arc differs from the radius start”. I changed tolerance’s, tried various options in the post-processor. I re-drew my part yesterday but haven’t been able to try it yet.

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#16

At the end of the day this is y’all’s decision. I’m just surprised at the result. As I said, never seen a machine shop chose a cold cut saw over a horizontal band saw.

For the record, the type of vertical band saw Nick and I are talking about is usually set up with rollers on either side, has a vice, and auto infeed. The blade is oriented so cuts move towards and away from the column, which is 90degrees to a more traditional vertical band saw, and the column moves in relation to the table. Marvel is a very common manufacturer. They’re a direct replacement for horizontal band saws.

The horizontal band saw DMS has is quite poor and hardly a fair comparison to a proper model with auto downfeed. I have seen the saw in the warehouse and I’m excited to get it in use, though it does need quite a bit of cleanup.

#17

I think it’s a matter of scope and speed. A CS will probably never be found in a job shop. It’s intended for high production. I know we were going thru (80?) 12 foot long bars of 2" steel a night. That would have taken a week to do on a regular saw. But as an aside, the CS we used a band blade rather than a circular blade but was a CS none the less and had automatic feeders, coolant, hydraulics and a hefty price tag. The other places I’ve worked all had Rollin’ type vertical saws. But then they are job shops where 50 pieces is considered a large job so they aren’t going to put out that kind of money for light duty jobs. Eastfield used a horizontal band saw found at Northern tools for about $350 (I know I bought one too). But then they were only cutting a few pieces a week for class.
Now compare all that to what we do at DMS - it’s all pretty light weight work. We were getting by with just the VBS before the CS was brought online. The CS has simply added a large level of convenience and accuracy we didn’t have before. And it’s pretty safe by comparison to the bandsaw. The main problems with the VBS and HBS are the abuse they take from our members either trying to push hardened parts thru or literally standing on them and often using them without coolant or lubrication.
So bottom line, as a matter of discussion for purchases at the MS meeting, nothing is off the table if there is a great enough argument for it. The largest argument against new saws is probably that we already have 3 saws (4 with the Evo). cheers!

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#18

That explains why I haven’t seen them then!

#19

Did it actually spit out some code or just die in the post process. Can I assume it was F360 for the design? You can probably switch post processors to another lathe type and see if it clears. That should give you a quick base for comparison between the two post processors to see what is different.

#20

I was using the simulation in the Dynamotion software, right before you pull the trigger to turn.
Yes I have used multiple post processors, that’s why I am trying a different model.