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New to CNC - Buying First Mill


RetiredVegabond
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Hi all.

I'm new to CNC machines and about to buy my first mill.

I've acquired a contract to produce components and am now building the capability. I know that sounds backwards but the opportunity came from the relationship with the client, not the existing capability. That aside, I could use some advise choosing and configuration the mill.

 

The application is predominantly drilling with some face milling, pocket milling, thread cutting and a little bit of hard milling (RC60). The parts are to be manufactured from square bar tool steel.

 

I've already got the ball rolling with a variety of equipment vendors and narrowed my options to the following:

Doosan DMN-500

Haas VF-4

Fryer V-40

 

I bought a copy of X7 mill level 1 to ensure I get as much out the mill as I can.

 

The mill is intended to be run lights-out and will be configured with the following:

Through spindle coolant

Probe package

Automatic tool changer

 

Undoubtedly I've overlooked an important parameter and I have a pretty steep learning curve. My apologies in advance. At the moment, I'm endeavouring to weigh the value of the following to determine which mill to purchase.

20 hp versus 30 hp

BT-40 versus CAT-40 spindle

Big plus spindle versus standard

Mist collection

Comparative rigidity and durability of the noted machines

Comparative strength of service network in SW ON.

10,000 rpm versus 12,000 rpm (excluding effects on cycle time)

 

Thanks in advance for your help. I look forward to your comments.

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prolly cant go wrong with the Doosan or Haas.

part price, support and service are untouchable on the Haas, in this class. big plus= you are out of luck on the Haas. Cat40 have a little thinner flange so that would be an advantage in tool overhang, but not by much,

 

unless you want to do deep hole drilling or exotic material drilling, forgo the through spindle coolant.

10k vs12k is not goig to be huge. i really like the Haas 12k spindle. lots of nuts for a Haas. can't compare that with direct experience on a Doosan, but have only heard good things generally.

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Doosan DMN-500

Haas VF-4

Fryer V-40

 

20 hp versus 30 hp

BT-40 versus CAT-40 spindle

Big plus spindle versus standard

Mist collection

Comparative rigidity and durability of the noted machines

Comparative strength of service network in SW ON.

10,000 rpm versus 12,000 rpm (excluding effects on cycle time)

 

 

Welcome to the forum!

 

New to CNC and hardmilling / threadmilling lights out and 60Rc right out of the gate... wow!

Hopefully you have a good background in Machining,

 

 

"20 hp versus 30 hp",Horse power will be the least of your concerns

"BT-40 versus CAT-40 spindle", just affects the thread and V flange of the tool holder (I think they are the same price for holders)

"Big plus spindle versus standard", Big Plus gives better rigidly and you can run standard holders in that spindle

"Mist collection", if you can afford it get it

"Comparative rigidity and durability of the noted machines", IMHO the Doosan DMN-500 would be your best choice out of the models you list.

"Comparative strength of service network in SW ON.", the dealers would be Fero Technique, Sirco, and SMS, all execlent Machine tool dealers and will stand behind their products.

"10,000 rpm versus 12,000 rpm", depends on your tool size smaller tools faster RPM, todays day and age get the fastest you can.

 

SMS also sells the Kitamura line, if I were doing Hard Milling I would look at that one, price point will be higher but you get what you pay for :)

 

Have those dealers cut your part on their machine in front of you before cutting a P.O. The right machine should be obvious.

 

Allan

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Can't go wrong with a Haas or a Doosan but it's important to know what you get with each.

Haas also does a couple of things differently from everyone else in the industry.

 

All Haas CAT/BT 40/50 Taper machines use the very same spindle cartridge.

If it's a 40 taper machine, regardless of size, it has the same cartridge as a Mini-Mill.

Ignore Haas ratings for HP and Torque as they are only based on a 5-minute rating.

The Haas will be cheaper than a DoosanDNM500 but keep in mind that the DNM500 will also

outperform the Haas in High Speed Machining and accuracy for high-tolerance work.

The Haas will be a bit of a disappointment for hard-milling.

 

Bob Wolcott has a few videos posted here where he compares his Haas to his Makino.

That's the kind of difference you'll get between a Haas and a Doosan.

I'd take a look at Makino as well.

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I'm a BigPlus fan personally.

BT tools have equidistant drive keys. I also like BT a little more than CT. The bigger flange carries a bit more rotating mass which can help dampen vibration a bit. Couple BT with BigPlus and you've got about as dampened and rigid a connection as you can get.

Get the machine prepped for High Pressure Coolant. You just never know...

20vs30... Can you ever have enough HP? :rofl::D

Mist Collection, yep, if you can.

10k vs. 12k is not a huge difference. Generally lower speed spindles last longer but that does not seem to become a factor until somewhere around the 15/18k range. All things equal I'd go with 12k.

 

For right around the price (I believe) you're looking at spending with the machines you listed, Matsuura VX Series warrants a look/test

http://www.matsuura.co.jp/english/contents/products/vx.html

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The application is predominantly drilling with some face milling, pocket milling, thread cutting and a little bit of hard milling (RC60). The parts are to be manufactured from square bar tool steel.

 

 

Spindle Through Coolant is the only way to go. I hate not having it limits me to the type of carbide drills I can use and in 60RC you don't want to be running HSS.

 

Good luck though and welcome to the forum.

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general size of parts might be good info.

would a mill turn be something to consider? just trying to think outside the box a little.

bar feed in mill turn may come into play for lights out production? otherwise you are going to need to tool for multiple parts- dont forget load unload times. how many sides do you need access to?

 

just some food for thought.

can you post pic of your parts proposed for production?

welcome to one of the greatest places for machining information, am sure you will get plenty of help here.

Doug

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No one else has said it so I will.. a lot of what machine your going to get is going to depend on the tolerances of your parts.. I currently work in a place where we do aerospace parts that tend to be very critical.. we do a lot of hard milling that used to be grinding ops as an example..

 

Some machines we tried were unable to consistently hold close enough tolerances.. others were able to run very tight tolerances reliably with no fuss whatsoever.

 

So if your parts are going to be very fussy.. then consider spending the extra money up front for a better machine cause otherwise you will pay with lost parts and or extra time and labor making them.. all machines are certainly not created equally when it comes to precision.

 

HP depends on part size for a lot of things.. I mean on smaller parts with smaller tools .. HP wont be much of a consideration, start running 5 inch face mills and or big drills its going to be a big issue..

 

Through coolant.. just an example.. on a drilling job recently we switched from a machine without it.. to one with it.. and saved 40 minutes per part on a part with 16 holes 2 inches deep.. pretty sure one job like that would pay for through coolant.. I would never consider getting a machine without it unless it was either used with no option or was to be dedicated to a job where it was absolutely unnecessary

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Another positive to spindle through coolant is it increases your edge life and also helps with chip evacuation which becomes a factpor when you don't have a operator to blow the chips off the part as the chips build up on it. As for the price I don't think Doosan can't be beat but bare in mind the Fanuc controller is no where near as user friendly as the Haas control so the learning curve will be greater. Not sure what your lead time is for your first delivery but you should take that into account.

 

First time you jam your tool changer you will know what I mean. On the Haas you press tool changer recovery button. It asks you a couple yes no questions and you are good to go. Doosan not quite as easy. when you have to run the machine through the tool change sequence.whether you do it from the manual panel at the back or through service mode and trigger it using m codes.

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Doug,

The parts are roughly 19" x 19" x 2". I don't have a picture at the moment. All six sides need to be machined. All the drilling will be done from the same side.

 

Dj,

The tightest tolerance that I need to maintain is a 0.005 window.

 

WAT,

I like the sounds of a one button recovery... Do tool changers jam often? If I'm using X7 to write the programs will my direct involvement with the control be limited to inputting tools and loading programs?

 

Thanks for all the input so far.

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How many parts are you going to produce? How much metal will you be removing? Machining a lot of steel? For getting started with small runs and aluminum I would recommend (gulp) a Haas. It will do just fine for that but if you are into a lot of steel and higher quantities the least expensive machine (Haas) will end up costing you $$$ every day in lost productivity. The cost will far out pace the difference in purchase price. A nicer machine whether Makino, Matsuura, Okuma, etc... will get you WAAAY ahead in short order if you are doing production work and removing serious metal. If you are hauling freight do you want a big rig or a pickup truck? Pretty much the same goes for production machining, Higher end machines or Haas.

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Excuse me you need to produce 2000 a year????????? Sorry, but yeah I had to read that several times.

 

You should really do some math here. There is normally 2000 hours in a 40 hour week per year allowing 2 weeks for vacation. We give you the benefit of the doubt and say you magically figure all of this out and get to 150 hours a week of production capability on a Vertical and sorry IMHO never going to happen that would give you 3.75 hours to machine these parts complete and meet your 2000 parts per year goal. You are cutting Mold grade material and expect to machine is complete in 3.75 hours using a Vertical? You really need to call in an expert from the machine tool companies you are dealing with and let them see everything. Everyone of the companies I have ever dealt with had people on staff that could evaluate what you are trying to do and give you the best process to do it with. A Vertical would be my absolute last choice. A Horizontal would be my only choice with at least a pallet changer. Any 400mm machine would do the size you listed with no problem and allow you the ability to run 2 at a time on a tombstone maybe 4 if we squeezed it. Give you the ability to get to 3 side on one operation and to the other 3 sides in the next operation. Plan according to your delivery and meet your 167 parts per month requirements. Look to a probing system, broken tool detection and 120 tools to start maybe more so you can make backup tool groups to keep that machine running lights out like you want. Chips will be falling away from your parts not stacking on the table that a vertical creates and life is good. 1000 PSI coolant system and 500 gallon backup replenishment tank with air agitators to keep it from building up bacteria. If programmed correctly and the right tools are used might get away with cutting most of it dray, but again would need to see the parts and not guess like I am doing now. Use top of the line holding system like Rego-Fix or Nikken SK getting away from Shrink. go with the Big Plus since looking a CAT40 machine going down to a 400mm. Do a search in this topic area been many discussions about going the correct route and sorry to say, but you are already starting in the wrong direction thinking Vertical.

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Bob,

I'm aiming to produce about 2000 parts in a year. Material is mold steel. About 1/2 the material is removed during machining.

 

Does anybody know the difference between spindle bearing diameters for a Haas VF-4 and DMN-500?

 

A Haas will be a huge disappointment for sure. I agree with Crazy Millman though budget could be an issue. A horizontal is going to be double the cost of a vertical (triple the cost of a Haas vertical) but you will get triple the productivity.

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Not to dissapoint, but the best thing you can probably do is get into bed with a company who can do this for you, and take 10%$ off the top of the job for 'managing' it.

 

Otherwise it's a Hori and a H U G E learning curve with programming and machine. Plus the expense and the probing to allow unmanned running.

And heaven forbid you have an accident on it - we had a small bump on a HG400 a few years ago and it was a small bump, but it still cost £25k.

And being realistic, you can gear up for all of this and your Customer can pull the job at any time, contract or not. And unless you have bought all your investment for cash, there's then a huge monthly finance bill to pay...

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Bob, time is money and money is time it is all relative as I know you are very aware of. Do you want to live at your place or do you want to invest in something that will give you freedom to know it is working day in and day out without you having to live there. I just passed on a $20 Million project because I could not come up with the $10 Million needed to get the right equipment. Sorry but 2 machines would have run the job for 10 years with 2 people working 40 hours a week. 4 machines would do the job cheaper in cost of equipment up front ,but would have required 20 people all working 40 hours week for the next 10 years. Let's take this example and see where the cost really comes into the equation.

 

$10 Million upfront cost. $8Million in Equipment going to fully lights out production capabilities. $2 Million the same cost for tooling and fixture shared by either process.

10 years would be $.8 Million in machine cost per year with 2 employees at 40 hours employee cost per year at a modest $25/hr would be $100K a year or $1 Million for the 10 years. If we made the $2million our total operation cost for the 10 years to produce all the parts we have $200K per year. Out Total sales is $2 Million a year so per year we can expect to net a profit of $900k per year or over the 10 year period $9 Million in profit by spending more money upfront on the equipment.

 

Cheaper machines that require far more labor. $2 Million on Equipment that only last 5 years and needs to be replaced after 5 years and $2 Million on the fixtures and tooling. $20 Employees on the modest $25/hr gives us a yearly employee cost of $1.25 Million. So in the 10 year contract we would be looking at $12.5 million in labor costs, and $6 million in tooling and equipment over the 10 year span. Our total operation cost for the 10 years per year will be $1.85 Million per year. Out net profit per year will be $150K per year by going with the cheaper less reliable solution. Yes I know my logic is completely crazy, but again I do Millman to the power of crazy all the time so I am used to it.

 

People always keep trying to show me I am wrong, but customer just bought a new machine to replace 2 older cheaper machines. They originally figured the one machine would keep even with the 2 machines that required more labor to keep running. After everything is said and done with the process I help put in place they are now wondering what to do with the extra 8 months of production they will be gaining with the new machine over the 2 older machines. They are now looking at increase of sales of 25 to 30% because of their increased capabilities. 8 months of gained production over their current methods. Do some math standard cheap shop rate of $50/hr for 100 hours per week of manufacturing capability in this example. 8 month times 4 weeks gives us a modest 32 weeks. 32 weeks times $5k a week gives a net return per year on the investment of $160k, but using my 2 for 1 rule since that is now time we are putting on work we really gained $320k in profitability using a very cheap $50/hr shop rate. We start getting into the $200/hr shop rate some places have and you start seeing some real money on an investment of $500k for a brand new machine verses staying with 2 cheaper same capacity machine the company had before.

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Crazy, I agree 100% but it sounds like this guy is just getting into business and this will be his first equipment purchase to support this one job. For me, I would not go out and buy a horizontal machine for my sole customer that planned to send me one job. There is a lot of risk in that. I only bought my horizontal when I had a diverse customer base and I was 100% positive that MULTIPLE customers could disappear and I would still be okay. If this guy delivers one order of bad parts and the customer goes elsewhere he will have one hell of a payment to make until he finds another source of income.

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And unless you have bought all your investment for cash, there's then a huge monthly finance bill to pay...

 

SBA Loan. These allow you to finance over 10 years and the rate is very good. My payment on the Makino horizontal is $1210 per $100k borrowed. It was a real pain in the -ss to get the loan and no way could someone get one without any business/ earnings history. Very good option for large purchases though. Keeps the payment low and really helps with cash flow when things slow down or you are sitting on a pile of receivables waiting to get paid.

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Thanks for the input guys. I've gone over the numbers in great detail and the margins are good. Millman makes a good point: 2000 pieces will be unattainable. The part I described above is the worst case. It's difficult to say specifically what the demand will be (long cycle time parts or short) since this is a family of parts and the customers order mix will vary every week. I had one of the equipment vendors run a simulation of run times. They concluded that the run time of my parts ranged from 26 minutes to 5.5 hours. I'm betting reality is more like 1-8 hours. Rerunning the business case with 1000 parts still makes this a viable project assuming the average part requires 4 hours. My financial situation prevents me from adding any additional equipment (or more sophisticated/more expensive equipment) until the cash flow from this job kicks in. Of course that's dependent on how much I need to spend on work holding and tooling. I should probably also note that production rates are planned to ramp up over the first two years.

 

Where do Schunk, Iscar and Sanvik tool holders fall in the hierarchy of quality?

 

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Bob just putting out facts and comes down to where you want to go with the direction. Everything is a risk, but sounds like this one is sewed up and now how does one go about making it work. $370K for a machine seems like a lot, but I know some of the players are willing to give you 12 months with no payments to help people get started. You come in with a P.O. in hand for 12 months worth of work is opens people's eyes. Come in with 4 years worth of work opens them more. People were jumping at the chance for a 10 year locked in deal. I might have got the right people in place and might have been able to get the ball running, but passed it over to people needing work and let the chips fall where they may. I am happy doing my thing helping the companies I can and doing what puts food and the table for me and my family.

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