New to Horizontal Milling

[g huns]

In our continuing effort to join the 21st century, we recently turned on the high pressure pumps on 3 of our vertical mills that have been dormant for 10 years and began using coolant thru drills. To say that it opened some eyes would be an understatement. We are saving days on our mold cavities, not just hours and minutes.

 

The downside is that these three mills also have to do most of our 3d finish work and being verticals, there is limited room under the spindle to put holes in the 4 sides of our blocks. These side holes tend to be deep, up to 16" long, 7/16 diameter, for water lines in the mold cavities. I have watched how we currently process these holes. It involves an 18 year old kid who doesn't know how to sharpen a drill, a manual boring mill, and a print that may or may not be the current rev level. A deep hole like this can take up to an hour. We also recently stopped building our own mold bases which frees up a programmer. That led us to start exploring the option of a horizontal mill. Since we recently blew our budget for the year, and probably next year, on a 5 axis mill, our options were limited. To give up a year to 18 months of increased productivity while the boss saves pennies for a shiny new Makino A61 would blow. So we took a big gamble on a used, and probably abused, Okuma MA-500HB. It's a 2005 with an OSP-P100 control. I have to find the room for it, make sure it runs, fix what's broke, and tool it up in the very near future.

 

Where the hell do I start?

 

I feel pretty good about tooling for milling in it. We have a decent amount of CAT50 Nikken mill chucks, arbors for carbide insert face mills, high feed mills, etc. But tool holders for drilling, not so much. 

 

It's a CAT50, 12K coolant thru spindle with the standard 60 position tool changer. We use Haimer shrink fit holders on all our CAT40 verticals, but those holder do both drilling and 3D finish milling. They seem too pricey to just drill a hole. I haven't been thrilled with any "sealed" collet holders we have tried. Are there any decent ones out there? We will be drilling holes from 3mm to who knows how big.

 

Workholding? Holy chit, how am I gonna hang onto this stuff?  I can see a few tombstones with vises for our smallish stuff, but when I have to hold onto a 28"x28"x10" thick block, where I need it centered on the pallet to be able to rotate the c axis or even run the pallet changer, what do I clamp it to? Are there angle plate lookin thingies where your workpiece nests on the inside of the angle? Who makes them? Do I have to make it myself?

 

Is there a book called horizontal milling for dummies I can buy? Does an OSP control have an easy button? I have hundreds of questions, but what scares me is the questions I don't even know to ask yet.

[cncchipmaker]

As far as work holding is concerned you could qualify one face of your block with a face mill, drill and tap some holes, and ream some holes for tooling. You would have to make a fixture to mount the block to. This is how we handle all of our large parts and I am sure you would have room to do this, especially if you are going to be removing most of the material anyways for the mold features.

[Bob W.]

Setting up a horizontal to be efficient takes a lot of thought, work, and $$$.  If done right it will be an amazing asset for the shop, if not done right it will become a boat anchor that a struggle to run.  For the drilling, to me it sounds like those are pretty expensive drills so I would spend the money and buy dedicated holders for them.  Do you know if the machine has probing?  If not this is a must.  A well set up horizontal can sit and run for hours if both pallets are loaded up and if your roughing tool breaks you can scrap a spindle or worse if the machine doesn't have break check capabilities.  On my first horizontal (Makino A51nx) I think I spend $40-$50k on tombstones, fixtures, and tooling to get it set up.  When I buy additional tombstones I also buy additional pallets so they are permanently mounted.  It would also be good to get a gantry crane on that machine if you don't have crane capabilities currently.

[Bob W.]

Another thing to consider is where the tombstone's center of gravity is once your material is loaded and what the pallet change load capacity is for the machine.  If the CG is too high or offset the pallet can get dumped during the pallet change.  I'm not sure my A61 could even change pallets with a 28" x 28" x 10" (2100 lb) block of steel mounted to a tombstone (600 lb) or other fixture as the rating for the machine is something like 1200 pounds.  You should look into the load capabilities of the Okuma to verify.  Also look into the safe working cylinder diameter of the machine.  If that block exceeds this cylinder you will get one hell of a surprise when you try to change pallets or index once in the machine.

[g huns]

Another thing to consider is where the tombstone's center of gravity is once your material is loaded and what the pallet change load capacity is for the machine.  If the CG is too high or offset the pallet can get dumped during the pallet change.  I'm not sure my A61 could even change pallets with a 28" x 28" x 10" (2100 lb) block of steel mounted to a tombstone (600 lb) or other fixture as the rating for the machine is something like 1200 pounds.  You should look into the load capabilities of the Okuma to verify.  Also look into the safe working cylinder diameter of the machine.  If that block exceeds this cylinder you will get one hell of a surprise when you try to change pallets or index once in the machine.

 

I believe, not 100% sure, it's about a 800mm cylinder. I think weight wise, it's about 1800 lbs. But that's just a suggestion, right?  

 

Thanks for the CG tip. Wouldn't have thought about that until one tipped over. 

 

I have seen people mount large blocks using the FCS system Makino pushes. That seems like it would be a flimsy setup, but I guess it's working for them.  

[Bob W.]

I believe, not 100% sure, it's about a 800mm cylinder. I think weight wise, it's about 1800 lbs. But that's just a suggestion, right?

 

Thanks for the CG tip. Wouldn't have thought about that until one tipped over. 

 

I have seen people mount large blocks using the FCS system Makino pushes. That seems like it would be a flimsy setup, but I guess it's working for them.  

Makino says it can do more but they will not guarantee accuracy if that weight is exceeded so I think it is partly related to the machining dynamics along with the pallet change capacity.  I would assume Okuma is in a similar situation.

[g huns]

Makino says it can do more but they will not guarantee accuracy if that weight is exceeded so I think it is partly related to the machining dynamics along with the pallet change capacity.  I would assume Okuma is in a similar situation.

 

The new Makino we had quoted has sensors that know the table load and adjust the machine dynamics accordingly. Same for tools in the tool changer. It's pretty sweet. 

 

I got some info from our local Okuma dealer. The thing rapids at almost 2400IPM and has .7G of acceleration. That seems crazy fast for as big as it is, and as old as it is. Our new 5 axis Roeders goes that fast and has 2G of acceleration, but it ain't very big and has linear motor instead of ball screws.

[T_MALENA]

Bob is right on the weight of the pallets. If both pallets are setup with equal amounts of tombstone/fixture/part you can get to the max weight capacity without issues. If you have say 500# on pallet #1 & 1500# on pallet #2 it harder on the machine "pallet change column" than having 2250# on #1 and 2250 on #2.

 

Also change the coolant gland on the back of the spindle!  Its 2 carbide faces pressed together to form a seal. The coolant passes through the glands. So 1 carbide face is on the moving spindle, the other is fixed to the machine base(more or less) and doesn't move. When this is neglected you dump coolant in places you'll wish you didn't.

[T_MALENA]

Also maintain the z axis way cover(s). these take some abuse from setups...dropped tools, operator standing on them etc.

[g huns]

Bob is right on the weight of the pallets. If both pallets are setup with equal amounts of tombstone/fixture/part you can get to the max weight capacity without issues. If you have say 500# on pallet #1 & 1500# on pallet #2 it harder on the machine "pallet change column" than having 2250# on #1 and 2250 on #2.

 

Also change the coolant gland on the back of the spindle!  Its 2 carbide faces pressed together to form a seal. The coolant passes through the glands. So 1 carbide face is on the moving spindle, the other is fixed to the machine base(more or less) and doesn't move. When this is neglected you dump coolant in places you'll wish you didn't.

 

When I found out our Mikrons had coolant thru spindle, I was scared to try it. The seals on those are supposed to be replaced every 8K spindle hours and our have over 20K hours. Not one of them has leaked... yet.

 

I am planning to get a quote from our Okuma dealer to have a service guy come out do a PM. Can't wait to see the price for that.

 

We have a good machine repair guy that we like and who is very reasonably priced, but I would feel better with an actual Okuma guy giving it the once over. I'm sure they are more familiar with what is likely to need attention.

[T_MALENA]

I think the max on the MA500 I had was axis travel X27,Y35,Z30 and the workholding/work piece was 32dia x 39 tall. something like 1700# pallet capicity

[T_MALENA]

where you located?

[g huns]

where you located?

 

You're not buying Rock Ridge?

 

North/central Indiana. I can spit to the toll road out my office window.

[MIL-TFP-41]

are your molds out of ferrous material?

Magnets are great for that kind of work. All 4 side of the part, no worries about clamps.

[mkd]

woulda been cheaper to put 18yo kid on a radial drill.

 not necessarily better. lol.

 

 I tried to compete against a radial drill on a CNC back in the '90's. Got royally smoked.

[YoDoug®]

Just tip your head 90 degrees and its like you are running a vertical machine

[g huns]

are your molds out of ferrous material?

Magnets are great for that kind of work. All 4 side of the part, no worries about clamps.

 

Lookin into it. We run magnets on most of our verticals. Love 'em.

[Mr. M]

Stevens Engineering has a lot of modular work holding for HMC's. Tombstone City also has a selection of tombstones. I like looking through sites like those for ideas

[g huns]

woulda been cheaper to put 18yo kid on a radial drill.

 not necessarily better. lol.

 

 I tried to compete against a radial drill on a CNC back in the '90's. Got royally smoked.

 

Back in my apprenticeship, I was the fastest radial arm driller in da west... No, in the WORLD.

 

But even on my best day, I doubt I could touch a modern, solid carbide drill with 1000PSI coolant thru spindle.

[jlw™]

Stevens Engineering has a lot of modular work holding for HMC's. Tombstone City also has a selection of tombstones. I like looking through sites like those for ideas

Tombstone City is great for browsing for ideas.

[Sticky]

I machine injection molds on a hmc. I can take some pics tomorrow when I am back at the shop. It's pretty sweet to do a 7/16" waterline 16" deep in 2min

[g huns]

It's pretty sweet to do a 7/16" waterline 16" deep in 2min

 

That's teh plan

 

I've told the boss for years, it's the BS work that kills us. We can 3D finish cavities with the best of them. We have three of the fastest graphite milling machines that exist. But it takes us an hour to drill freakin water line.

 

Investing in the boring stuff like drilling holes and roughing blocks was never considered. The technology we use for that stuff is straight outta 1980.

[Sticky]

HMC's for mold bases, and even for inserts is pretty awesome. I can hit all 6 sides of a mold base in 2 ops, likewise with inserts. All the meanwhile I can get everything within tenths and avoid most grinding work.

[jlw™]

Blow the dust off that thru coolant and drill the holes man.

[g huns]

Blow the dust off that thru coolant and drill the holes man.

Oh, we are. I bet I've spent 10K on drills in the last month. The Walter-Titex guy better be sending me some nice swag this Christmas.