[slatern44]

I dont know if this is the correct section to put this in but I want to hear from other haas owners so here it is. I have to mini mills now that run pretty much run all of the time at there max capacity. I mean 6000rpms and 3 double lock vises on each and pushing them as hard as I think the tooling can handle. I run my shop with lots of soft jaws and dedicated tooling to set up can be less them 1 min or sometimes 5 min if I have to change jaws. My reason behind buying the two mini's was two spindles were better then one. VF-2 almost $60,000 and mini's $34,000 per. But now I need more capacity and I'm looking at a VF-2 and just wondering if now is the time to buy one or just get another mini. The parts I make are small, most are titanium and aluminum and less then 6" long and 2" wide. So I dont need a big machine but If I get a big one I could put more parts on and the machine could have a long cycle time.
I know everyone that I ask will give me a different answer but I thought I would ask anyways.
Thanks,
Neil

[gar]

071014-1330 EST USA

slatern44:

Do detailed analysis of your cycle time including loading. Calculated or measured best possible part to part time. Also determine the time to do a day's worth of work, punch in to punch out time. Divide this by the number of parts made. Compare this with your best possible time. Can there be any improvement at low cost.

Try to estimate the same times using a VF-2.

If you have a lot of tool changes per part, then loading more parts for one machine cycle may be advantageous. Could you effectively use a high spindle speed. This may be hard to predict the results without experimentation.

I would favor the VF-2 because I like the package better, but it may not be your lowest overall cost. More less expensive machines may be better because of the redundancy. One machine down has less effect on your thruput.

.

[big_mak]

Slattern,

Have a look at the Horizontals. You get pallet changer, and by the size of your parts, you could put a 4 sided tombstone up that would be the equivalent of 4 dual station vises per pallet.

[slatern44]

I was thinking of the VF-2 with the 10,000 rpm spindle and pretty much just use it for my aluminum jobs. Then I could leave my two minis for the Ti and damascus work where I dont need the high rpms. Most aluminum jobs that I do are around 500-2000 part run and all ways need 10 tools or more so the 20tool change on the VF-2 would be nice.
About the horizontal I dont think that I do enough volume to need one. But maybe someday. I'm just a two man shop so if by buying another machine and it sits some of the time but it lets me have a Saturday or Sunday off to me that's worth it!!

[big_mak]

I've got the 10K geared Head High Torque Option on my VF-3 as I'm jobbing.

Look on the Haas web page, and price em out. Say with an EC-300 you could probably sell one of the mini's off and put that $$$$ towards the machine.

I have a jobbing shop, so I don't know what's coming in the door one day to he next, so I can't shoe horn my self into small parts, but if you have small stuff, nothing beats the outsput of a horizontal. I've run a few and man they are quick.!!!! They could definately get youthe weekends off!

[gar]

071014-1548 EST USA

slatern44:

Needing many tools seems to answer your own question. Also there times when you can not use adjacent pockets because of tool size.

If you write your programs so that you sequence thru all the individual parts with each tool change, then you save a lot of time, and wear & tear on the machine.

.

[slatern44]

I need to spend some time like gar said and re-program some of my parts with the idea that I have a larger machine and faster spindle. A couple of the companies that I work for have told me that to plan on getting very busy in december because of new product launchs for next year. And I'm maxed out now, cant work 12+ hours a day 7-days a week forever. I guess this is just some of the growing pains of young small companies.

[Geof]

...... I guess this is just some of the growing pains of young small companies.

I looked at this thread and had decided not to comment because other people had made the points I would make but then changed my mind. My suggrestion is that not only do you take gar's advice you also take a step back and look at what you are doing and what type of commitments you might be making. Young small companies often go down the tubes because they cannot make a go of it...they can also go down the tubes because they are too successful. I know this seems contradictory but it can occur if your customers get the impression that you can perform beyond your capabilities. Then if something comes up that you cannot meet their expectations...even if their expectations are completely unrealistic...they get really pissed off.

With this in mind I suggest you do not make a choice that involves being dependent on one machine; as gar says if you rely on one spindle and it goes down you have a real problem.

[slatern44]

Thanks for the advise. This is why I'm trying to grow slow (machinery) and work a little harder now. Well I have to get a third machine just need to decieded on another mini or go for the bigger machine.

[Geof]

Look into going for two Super MiniMills.

10,000rpm spindle, 1000ipm rapids (or something like that) and a much faster tool change.

I have two MiniMills and three Super MiniMills and would never buy another MiniMill. Two of my Supers also have the Z axis lift which gives more Z clearance (but not more travel) and I would never go without this because it allows for the use of a HRT210 rotary. I also have a VF2 with the umbrella type toolchanger and two VF2 with side mount tool changer. And our work is all aluminum 50 to 1500 parts per cycle.

My bottom line advise is get two VF2 with side mount toolchanger. This gives you the security of not being dependent on one spindle, allows you to leave tools in the machine between jobs and gives you much faster tool changes than with the umbrella toolchanger.

But it also means you need to come up with about 130 grand which I will admit can be a challenge.

[Rocko1]

Also, I have seen many young and old companies go down the drain on buying equipment for anticipated workload and not actual workload. I would never buy equipment for possible work, only actual work. So do not consider the potential increase coming in December, but what your workload is currently.

[slatern44]

Rocko1. I do agree with you but you have to keep growing and reinvesting back into your company. I have been able to pay off both of my mini's in less then one year and now need another machine to help build more business and take care of current overload. I guess more of the question or answer I was looking for by posting this was do you buy what works or buy bigger because you know someday you may need it?

[Rocko1]

Always buy a little bigger, look at it as capacity to grow (as long as you can afford the increase in size). You may machine smaller stuff currently but later you may need to do bigger work or perhaps more multiples with one set up as stated by some above. I know we could have done fine with a VF2 but went with a VF3 that will allow us to machine with one setup about 10% more of our jobs, because of the larger table and y axis .

[Edster]

If you considering another minimill why not look at the Fanuc robodrills? They are really fast. Here is a link with a vid.

http://www.practicalmachinist.com/ub...c/13/4459.html

[ducesrwld]

have you seen the new MDC-500 mill drill center. that could be of interest. same setup as the ec-300 but in a vertical. little bit bigger travels than the mini mill with a pallet changer.

[Kool Parts]

Slattern44,
One of the toughest questions a small business can answer. Mostly because there is no right or wrong answer. If you buy that $300,000 plus Horizontal and go out of business..you are a idiot. But if you do, and a customer walks in the next day with a job that needs that kind of capacity....you are a genius.

One way to look at it is in your case adding one more mini would not be throwing money away as they are doing the job now, and they are relatively inexpensive.
On the other hand a vertical is the most labor intensive way to machine.

[slatern44]

I had my sales rep out from Selway and it looks like the VF-2 is the best fit for what I'm needing. Of course it could be done on a horizontal or drill/tap machines but I want use this mill for 75% production 25% one off job shop work. But I have one more question. He did not have much good to say about the VF-2SS machine or any SS machines. He said they have problems with the spindle and ball screws because there pushing those machines so hard. Is this true of just his opinon? or maybe a couple of bad mills that he has seen or sold in this area? I thought it looked like a good package.
Thanks again,
Neil

[gar]

071019-0416 EST USA

slatern44:

Logic tells you the following if materials and tolereances of the components are approximately the same:
1. A lead screw with a larger pitch, fewer revolutions per unit length, is less stiff, a softer spring, and has less absolute accuracy per unit of angular motion.
2. Larger pitch produces higher linear velocity for a given angular velocity.
3. If no other errors are considered using the same angular encoder the absolute error will be greater on large pitch screw vs a lesser pitch.
4.F=M*A. Thus, for a fixed mass higher acceleration produces higher forces.

If you used a standard pitch lead screw your maximum linear speed is less, acceleration forces are less, and your accuracy will be better.

Is linear speed more important than accuracy?


Spindle speed. As this increases friction losses increase and temperature rises. Dynamic balance problems increase with speed. By using different spindle designs one can somewhat minimize these problems. There are also resonance problems such that for certain spindle and tool combinations on a particular machine maximum RPM may not produce best results.

A decision on a higher speed spindle compared to a standard 7500 RPM unit may be something you need to experimentally evaulate. With 4 standard 7500 RPM machines we have never replaced a spindle or lead screws. However, we do not work these machines hard.

.

[Geof]

Don't get the SS.

I have a VF2, 10000rpm spindle belt drive with 1000ipm rapids and a carousel tool changer bought in 2004 and run practically every day since then. It is running at 10000rpm most of the time taking decent cuts in 6061. So far the only downtime has been due to a broken drive belt when we ran the tool holder into the part. I also have two newer VF2s with sidemount changers and they have had no problems other than a software glitch.

Scan through the posts here and you will find a lot of comments about the SS machines, not positive comments.

[Kool Parts]

Most anything negative on the internet is exaggerated...but on the SS it appearers to be true. Just too many story's to make me comfortable.

If you get the VF2 definitely go for the side mt tool changer and 10,000 spindle. Those 2 will gain you a lot of speed over your current setup