Gun Drilling on Horizontal

[cunder]

I am gun drilling on a horizontal using just the basic water soluble coolant. Material is H13 but the tool does not hold up too long.

So just wondering if any one else is doing this. The reason for using a gun drill is the special size and the length that is needed.

Standard long carbide drill does not seem to be available.

[GoetzInd]

What kind of tool wear are you getting? What size drill and how much coolant pressure?

 

Mike

[Pilot Plant Supervisor]

I just gun drilled 2MM holes 3.5" deep in Titanium on our horizontal. 23 pieces with one tool! I used Guhring series 6400 drill to pilot the hole and series 5026 gun drill. I also have 1000 PSI through spindle coolant which is critical with a drill as small as 2MM. The Guhring catalog has a bunch of info on how best to enter the hole and such. From memory,it was something like drill pilot 2X diameter deep, enter hole with gun drill at 300 RPM and 20 IPM feed to 1.5X diameter deep. Start through spindle coolant. Start spindle at desired RPM. Drill to depth. Rapid retract to start depth (1.5X dia.) Slow spindle to 300 RPM and feed out of hole at 20 IPM.

[cunder]

Dia. is .377" some holes are 13" deep through. Not sure of coolant pressure as I am not sure how to read the gauge. It is just standard, not high pressure. Chip evacuation is good.

I am not sure to attach a photo but I can e-mail one.

 

[email protected]

[cunder]

I should have said I can e-mail a photo of what the wear on the drill is.

[Brando]

best u can do then is run as much concentration as possible maybe 10-15%

[Brando]

also make sure your not dwelling on your pilot hole or you can leave a hard spot where the drill stopped and this obviously will wear out your deep hole drill

[Hardmill]

Dia. is .377" some holes are 13" deep through. Not sure of coolant pressure as I am not sure how to read the gauge. It is just standard, not high pressure. Chip evacuation is good.

I am not sure to attach a photo but I can e-mail one.

 

[email protected]

 

Whats your speed and feed ??

Is your set up rigid ??

And are you feeding into a pilot hole first ??

 

 

 

 

 

 

 

 

PEACE

[Tim Johnson]

Dia. is .377" some holes are 13" deep through. Not sure of coolant pressure as I am not sure how to read the gauge. It is just standard, not high pressure. Chip evacuation is good.

I am not sure to attach a photo but I can e-mail one.

 

[email protected]

 

That is only 35xdia deep. Walter/Titex can make solid carbide coolant thru drills up to 70 times deep if you are repeating the gun drill process (probably a 6+ weeks delivery). Also you could get some 30x solid carbide coolant thru drills that would be in stock and finish the holes with the gun drill.

[cunder]

The solid carbide would be pricey. If the point geometry is similar I would be concerned about the same wear problem.

[taperlength]

Is the drill failing as it breaks through the other side?

[cunder]

The drill is not failing completely, and not when breaking through. It still drills, spindle load is good, tip does not look good.

[crazy^millman]

That screams wear which tells me you are taking it way to easy on the tool. You are rubbing the material verse cutting the material. I would leave my SFM where it is and maybe double or triple your feed rate and see what happens to your tool life. I have seen time and time again where someone slows feed rates down thinking it will help and then the opposite happens. Maybe not the case here, but it all else fail I go against conventional logic and start speeding things up. I have done that and seen some really amazing results I would have never expected to see with tool wear and tool life.

 

(Side Bar Crazy Logic)

No do not get in the trap of well we only got one tool because it cost so much money. Sorry if someone quoted the job wrong and did not take tool wear into account in their quote not your problem unless of course you quoted it. I also would look at if 1 tool drill the 10 holes 20 minutes and has to be replaced or one tool will drill 20 parts in 6 hours and only cost $300 then I always get more tools. Time is money and yes it is $600 worth of tools verse $300 worth of tools, but one tool cost so much more money not every funny. Hear or read me out. 40 minutes with $600 or 360 minutes with $300 a tool. Now basic math will tell us 2 tools comes out to $15 minute or $30 a part in tooling cost. The other way tells us is it $,83 per minute of tooling cost or $15 a part in tooling cost. Most managers get here and say you idiot you spent double the budget on tooling. I laugh and say nope you bigger idiot I saved way more than you budgeted. The one method saved 320 minutes of time, but cost double the tooling. Thing about time is people forger the 2:1 rule. For every minute I saved on a job I gain 2 minutes. Yes I did it 320 minutes fasted but really saved 640 minutes. So lets just use $60.hr shop rate here. $640 minus $300 means I really saved $340 on doubling the tooling on the job. So in all reality I saved way more money than I spent. People only see the cost of the tooling and not the cost of the time. I call this the un-captured cost of doing business. Everyone can put their hands on a tool, a machine or a part. Tell them to put their hands around time and give me a value. Most go well our shop rate is so and so. Going back to our example here lets say the shop rate was $120/hr so now we really saved $1280 minus $300 for the extra tool a total of $980 on this one job. Take 4 jobs a week where you saved an average of $1000 spending a little more on your tooling. In one year you just saved or made a profit of $200K. Yes that Carbide drill is expensive, but how expensive is that time you our wasting using the wrong tool for the job and how much would a scrap part cost you? Here I always use the 3:1 rule. You lose the original, The replacement and the time and effort not put on the next job. $1000 part boom $3000 lost saving $300. $10000 part boom lost $30000 saving $300. Yes really stupid spending the extra money on good tooling and pushing it to maybe not last as long to someone else's expectation.

[steveo25]

Does the tip angle of your pilot drill match the angle on the gun drill? and is your run out looking good?

[Brando]

That screams wear which tells me you are taking it way to easy on the tool. You are rubbing the material verse cutting the material. I would leave my SFM where it is and maybe double or triple your feed rate and see what happens to your tool life. I have seen time and time again where someone slows feed rates down thinking it will help and then the opposite happens. Maybe not the case here, but it all else fail I go against conventional logic and start speeding things up. I have done that and seen some really amazing results I would have never expected to see with tool wear and tool life.

 

i feel the same way about this, im thinking hes not loading the drill with enough chip load and when drilling the drill is winding up and springing back, chipping his cutting edge, the hole is 13" deep so his drill gotta be 13.6-14" long

and heres the pic of his drill tip, he sent me a few emails

im gonna try to dig thru some old notes i may have drilled something similar to this at an old job

 

he also said hes getting a honed edge prep and a coating put on

[Newbeeee™]

That tip looks like vibration has killed it to me???

[cunder]

Sounds like increasing chip load is the next step to try once the coating and honed edge is applied.