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HMC in a job shop?

KatherineNies12

Plastic
Joined
Jul 27, 2018
I am starting to think about adding another mill to the shop (getting spindle time bottlenecks) and a friend suggested that I keep my mind open to used horizontal machines. I know that having gravity help with chip control would be wonderful, and a tombstone with 2 or 4 usable sides could help with some common setups, but.... these things just seem very complicated and a little out of my comfort zone right now. Anyone running horizontals in a job type shop and think it is just the best thing in the world? A long job run for me is 50 parts with 5 hours of work on them, most runs are a couple of hundred 15 minute parts and I spend more time between prep/setup/post work than I actually have them in the machines. I am presently running a pair of 40x20 Okumas and bringing a Sharp 2412 back online to use for 2nd ops (no auger so chip mgmt. is a pain).
 
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I’ll take one horizontal over 3-4 verticals any day of the week if it helps you. But in the end it is your comfort zone, not mine. Get the biggest tool changer you can afford and keep your tools in the tool changer.
 
running a horizontal and vertical next to each other in a jobshop type setting, there is not much difference. we even use the same post. I would love if we had a rotary on the HMC though.

+1 on getting an HMC into the works with a giant tool magazine.
 
For big flat parts no but for smaller parts, can't beat 'em. It's not just "chips fall down." The spindle is about a gazillion times more rigid, you can stack small parts on four sides of a pallet and lots of times you can get to several sides of the part and while the machine is running pallet A, you can be loading and unloading pallet B.

Horizontals kick ass.
 
Get one.

We are a job shop, 1-10000 pcs, usually no more than a few hundred of anything of various sizes. 11 years ago we had none, but 9 vertical machines. Now we have 3 horizontals and 7 verticals.

Get one with a bit bigger tool changer capacity, about 100 tools. Don't think for a second that that is too many tools, you will keep half the tools in the machines as standards and the other half as random tools. You can even keep jobs set up on the machine with extended offsets (g54.1) and the tools that belong to that job.

We have one machine with 132 tools, another 100, and one with 40. I'm always wishing the 40 tool machine had more...

Have a stupid angle you need to put on a part? Horizontal. Need to hold tight location on 3 sides of a part? horizontal. Need a 12"+ indexer to do some holes or other features on the outside of a big round part that you can't fit in any of your indexers, and they weigh too much to lift? Horizontal with a crane.

They are not more complicated than a vertical, really. You will have a few more M codes to plug in, pallet lock/unlock, pallet change, pallet check command, etc. You will have to have to specify B0 any time you rotate the thing (or any time you change tools really), but I find the complexities end there.
 
horizontal can be more complex to program and fixture costs can be higher.
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tools sag and longer tools sag more gravity does have an effect on tight tolerances
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coolant often is like a fire hose coming from the ceiling blasting chips out of the way. works great if chips are short like with cast iron.
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grid shift and center of index calibration is slightly more complex on a horizontal
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multiple pallets that you setup and unload parts while another pallet in the machine is normally done. pallets cost money obviously if you buy 50 pallets and a automated pallet storage system that can cost alot.
 
many horizontals use dynamic work offset. say at table B0 the G55 is Z6.0000 when table rotated to B90 then it becomes X-6.0000
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dynamic work offset can be great when it works. if not used than you can program it to change the G55 although often its done in the macro or Mcode that rotates table automatically. if table rotation interrupted than it can get mixed up as it did not finish. hard to explain. when table rotation interrupted ? say operator notices a long tool will hit part and fixture during rotation and does a feed hold then a reset. that definitely will cause a need to check zero return and the work offsets. if G55 at B0 was written done than its easy to confirm its ok or not
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also on program restarts. better programs everything is reset to pull back tool, recall table rotation, work offset, tool offsets..... just saying it can be more complex programming
 
If you are comfortable and capable on a vertical you can become comfortable and capable on a horizontal quickly. You can make it as simple or complicated as you want. Options like dynamic work offsets are nice, but not needed, for 3+1 work, which is what you would be doing, you can just use a macro to calculate the other angles. Nothing difficult, just different from what you are used to. The horizontal will be far more productive than a vertical, if you are efficient at programming, and get repeat jobs, you will find your repeat setup times will go down (as long as you set yourself up with some sort of quick change system), and you will make parts faster. If you only run one side at a time, you will be wasting cutting time, but if setups are your bottleneck you would then be able to work on your setups on the other side while parts run, you would just have to pause for a bit while you load parts. Or you can buy a couple of spare pallets and swap the pallets with a crane, thus giving you the chance to work on setups while parts are running, leaving only a little indicating and whatnot when you can get it into the machine. Lots of ways to be efficient with short run work on horizontal machines.
 
When getting a used one make sure the pallet mounting system is in good order. Put an indicator in the spindle against the tombstone up near the top of Y travel and push on the tombstone with your hand. If there's a problem you'll be able to see a few thou movement.
 
on youtube, Edge Precision has several videos showing the use of an HMC with a couple of pallets to work on large work pieces that are surely done in low quantity. There is some more probing/touching off to set B rotation, but other than that it looks an awful lot like running a horizontal to me.

These two in particular seem relevent to OP's question:
Bottom Block Calibration block Set - YouTube
Top Blocks Calibration Block Set - YouTube
 
i use a horizontal often. some always use G17 and G55 no matter what, table rotation on others use G55, G56, G57, G58 depending on what side of part you are on
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some G43 always only effect Z and other machines if you used
G43 H1 X1.0 Y3.0 Z7.7 it will add length comp to all 3 axis on the line. basically with a parameter change you can limit G43 to only Z
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just saying they can get complicated programming and restarting and easy to make mistakes. post processor can take a lot of time to get working ok for a specific cnc
 
I am starting to think about adding another mill to the shop (getting spindle time bottlenecks) and a friend suggested that I keep my mind open to used horizontal machines. I know that having gravity help with chip control would be wonderful, and a tombstone with 2 or 4 usable sides could help with some common setups, but.... these things just seem very complicated and a little out of my comfort zone right now. Anyone running horizontals in a job type shop and think it is just the best thing in the world? A long job run for me is 50 parts with 5 hours of work on them, most runs are a couple of hundred 15 minute parts and I spend more time between prep/setup/post work than I actually have them in the machines. I am presently running a pair of 40x20 Okumas and bringing a Sharp 2412 back online to use for 2nd ops (no auger so chip mgmt. is a pain).

The programming should be a snap because it's just indexing, not live 4-axis cutting. Even if you program by hand, lol. Dream up what would be a good work holding/fixturing setup in a vertical then apply that to as many sides of a tombstone as you like. Sounds like a pallet changer would alleviate your setup bottle neck too. We have a number of horizontals and the work is more one-off than yours but the productivity theory is the same. Our workhorse is a Niigata SP901 with a two pallet setup. Even with doing our one-off, non-production type parts the 2nd pallet enables maximum spindle on-time.
 
major source of scrap and rework with horizontals
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1) restarts and modal gcodes not being restated at "restart here" points. obviously a tool can crash into part if it does move to the side (clearance) and tool pull back before table rotation. if table B axis not correct obviously can crash into wrong side of part
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2) resets forced cause machine wont respond for various reasons. if machine defaults to G1 G17 G90 G80 G49 G40 G54 and no feed stated any and all of the default gcodes can cause a problem. if G55 needed and only a little different than G54 it might take time to even notice
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3) grid shift and center of index error or calibration. obviously if you want 2 bores on opposite sides of a part to be same dimension from a perpendicular side cnc needs calibration
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4) i wound not say programming is easy. if you are machining 3 sides usually all the machining coordinates has to be in 3 dimensions. rarely are horizontals manually programmed. sure i can add a extra pass or create a hole slot or drill a hole manually but it quickly becomes complex finding 3 dimensional coordinates on parts that are not simple rectangles which majority of parts are not simple. and 3 dimension coordinates on a angled surface (not 90 degree) it becomes obvious the need for a CAD CAM program
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just saying if you collect scrap and rework data at the end of each year you can easily see operator mistakes and programming mistakes from complex causes of a horizontal cnc . setup information needs to be in more detail. hard to describe. usually i record all time delay issues and work on preventing it happening again. obviously if not done mistakes keep occurring. problem is some parts are very expensive so mistakes can be very expensive
 
major source of scrap and rework with horizontals
.
1) restarts and modal gcodes not being restated at "restart here" points. obviously a tool can crash into part if it does move to the side (clearance) and tool pull back before table rotation. if table B axis not correct obviously can crash into wrong side of part
.
2) resets forced cause machine wont respond for various reasons. if machine defaults to G1 G17 G90 G80 G49 G40 G54 and no feed stated any and all of the default gcodes can cause a problem. if G55 needed and only a little different than G54 it might take time to even notice
.
3) grid shift and center of index error or calibration. obviously if you want 2 bores on opposite sides of a part to be same dimension from a perpendicular side cnc needs calibration
.
4) i wound not say programming is easy. if you are machining 3 sides usually all the machining coordinates has to be in 3 dimensions. rarely are horizontals manually programmed. sure i can add a extra pass or create a hole slot or drill a hole manually but it quickly becomes complex finding 3 dimensional coordinates on parts that are not simple rectangles which majority of parts are not simple. and 3 dimension coordinates on a angled surface (not 90 degree) it becomes obvious the need for a CAD CAM program
.
just saying if you collect scrap and rework data at the end of each year you can easily see operator mistakes and programming mistakes from complex causes of a horizontal cnc . setup information needs to be in more detail. hard to describe. usually i record all time delay issues and work on preventing it happening again. obviously if not done mistakes keep occurring. problem is some parts are very expensive so mistakes can be very expensive

I held my tongue after reading your last couple replies to this, but I can't any longer.

Programming is easy. Plain and simple. You can program a horizontal by hand. I am doing it right now, to do some holes and mill around a square. I do this every day. It takes the same code as any of the verticals here, except you tell it which side of a tombstone to go to. Easy.

The work the OP seems to be doing is already being done on 40x20 machines, taking 15 minutes on said machines. I don't see any reason to throw dynamic fixture offsets into play.

You can crash a vertical just the same as a horizontal if an operator is stupid and hits the reset key and blindly hits cycle start again without checking clearances and whatnot.

Finding center of rotation of the pallet is no harder than finding center of rotation of a little 5C collet indexer on a vertical.

Really, you're the only one saying nay to such a machine, but you are not a guy in a jobshop doing lots of 50 parts that you can fit in your hand, and I don't think your spreadsheet knows any better either.
 
My vote is No. Not if your shop is like here, meaning orders of 100 is a LOT for us. We've got an HMC, but after the fact needed work that would keep the Spindle running. "Job shops" are about 60/40 Spindle on/off. So it makes money now, but we had to find a specific job for it to be profitable.

Bottom line is they are not faster to set-up. The rest you can figure out for yourself.

R
 








 
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