Thru spindle

[MIKEPETTY]

Hello. This is my first post, I've been lurking for awhile. Very informative site. The question I have is pertaining to drilling. The company I work for is looking at purchasing a new Makino vmc. The machine comes with thru spindle air but thru spindle coolant is a option. We will be drilling everything from 1018 to heat treated D-2. How much of a handicap will we be without thru spindle coolant? Will there be any advantage to using the air in drills with coolant holes in them? Thanks

[5axisguy]

In my opinion thru spindle air would be used for machining only, not drilling, thru spindle coolant makes an unbelievable difference in speed of drilling with no pecking.

[MIKEPETTY]

Thanks. I was under the impression that thru spindle coolant evacuated the chips and that in machining with carbide that it is better to use air. So I was hoping that using thru spindle air to evacuate chips and carbide drills would work in the same fashion. Guess not.

[5axisguy]

You are correct in saying that with carbide it is better to use air, I would use that rule for milling only, when it comes to drilling, thru spindle coolant with carbide is the way to go. You might be able to use the thru air with drilling, but with no where near the feedrates as with the coolant, we drill on our kuraki bar with the chipblaster which has about 750psi of coolant, and it was worth the cost of the option.

[RICHARD ZASTROW]

I had good results drilling with air plus one of those micro-drop dispensers in the air supply line. Careful, the air blasts chips all over the place.

Dick Z

[MIKEPETTY]

Thanks. Richard what kind of speeds and feeds where you seeing with the air?

[RICHARD ZASTROW]

We used whatever the drills recommended speed/feed was. Made time by not using peck drilling. Some were carbide, some coated high speed steel and some were indexable coated carbide. Whatever you use, it must break up chips. In fact, one suppliers brand name is "Chipbreaker Drill".

Gundrills can be utilized as well. Sterling etc.

If your machine is not a through-the-spindle-coolant type, rotary inducers are easily made and there are some commercially available.

Dick Z

[ctate2000]

The cost effectiveness of through coolant depends on the material and machining operations you are performing. If you only drill shallow holes and you are milling more than drilling you may find it is not cost effective. Remember to ask about the maintenance. These costs can add up when the coolant system goes down. It is a very useful option when the cost is justified.

[Mazaholic]

there are many other uses for thru coolant,drilling is just the tip of the iceberg.
Blind hole reaming,burnish reaming,tapping,hole forming tools,thread milling,boring.
If you machine alot of aluminum,thru coolant is your best friend.

[MIKEPETTY]

Thanks again. We machine mostly tool steels. I was hoping that air with a mister would get it done in the same fashion.

[RICHARD ZASTROW]

The micro-drop method is similar to the mister type systems except for the mess. When properly adjusted, the micro-drop systems use very little coolant. The mist systems tend to send vaporized coolant all over the place when the air volume and pressure are high enough to be effective.

The micro-drop systems actually are using the air to cool the tool & workpiece and evacuate the chips (swarf). Those bio-degradeable vegetable oils really act more as a lubricant for the tool than a coolant. They handle lubrication with heat very well. Think of the veggie spray for frying pans, the castor bean oil in racing engines or the jojoba bean oil in some water soluble coolants.

When properly adjusted, a micro-drop system barely moistens a white paper held in front of the outlet (drill point).

As mentioned on other threads, I've used this to mill 3/4" slots and "T" slots in steel press platens and used less than 1 cup of the fluid in 8 hrs.

You will detect the vapor in the local atmosphere but hardly irritating and according to the data sheet not harmful. If it bothers you, it might be in your best interest to avoid fried foods. lol

Dick Z

[mc-motorsports]

Originally Posted by ctate2000 The cost effectiveness of through coolant depends on the material and machining operations you are performing. If you only drill shallow holes and you are milling more than drilling you may find it is not cost effective. Remember to ask about the maintenance. These costs can add up when the coolant system goes down. It is a very useful option when the cost is justified.

+1

If your not going to make good use of the through tool cooling, leave it out, they require matenice and or scheduled replacement which means down time and they are generally expensive. And if not mantained and or replaced when needed, they leak and can ruin the spindle bearings, encoders, burn the motor, name it. You just have to be able to justify the expense, other than that, you can greatly increase your drilling speeds.
MC