DMF_TomB
Diamond
- Joined
- Dec 13, 2008
- Location
- Rochester, NY, USA
so had a job the other day running program as programmed.
1) drill bit new used less than 20 minutes
.
2) 10" deep horizontally drilled .375" dia hole, feeds and speeds in normal range with shorter drill depths has 99.999999% success rate per 100,000 holes
.
3) programmed to enter 4" deep .375 dia pilot hole at low rpm once in hole rpm goes higher and a G1 at feed given to 10" depth, when done spindle shuts off and it pulls drill out.
.
4) as often happens at high or low feed and 500 different in between feeds and speeds on a deep hole no coolant getting to drill tip and flutes hard packed with chips. no coolant ever getting through to the drill tip coolant. so drill breaks 9" into hole. happens about 5 to 20% of time based on data from last 100,000 holes drilled
.
5) 10 hours labor into machining part, broke drill often takes longer than 10 hours to remove. the drilling without pecking maybe trying to save 5 to 10 minutes drilling. at end of year broken drills taking at extra 50 hours of labor per year (removing broke drills or remaking parts) that was trying to save maybe 5 hours per year by not peck drilling
.
6) data from last over 10,000 parts and easily over 100,000 holes show peck drilling if done carefully like slowing rapids and having machine stop rapids and go into feed at least 0.1" away (parameter setting) to stop slamming into chip bur sticking up at hole bottom at rapids speeds. having peck not have drill tip come fulling out of hole but stay a 1" in hole to save drill tip whipping hurting drill tip on hole rentry with drill tip..... the failure rate peck drilling carefully is less than 0.01% the failure rate of trying to deep drill without pecking
.
7) just a observation that not pecking when deep drilling has cause 10x to 100x more problems than peck drilling. so who is one who figured not pecking is better when data from last 100,000 holes says other wise ?? .....and yes over 500 different speeds and feeds tried. failure mode 99.999% of time is hard packed chips clogging flutes increasing turning resistance til drill breaks. many materials like cast iron do not flow chips through flutes any better at higher or lower feeds from data on last 500 different settings tried
.
just observing its one thing to talk theoretical peck drilling is bad, its another thing dealing with broken stuck in hole drills and remaking parts which normally are causing 100x more problems based on last 100,000 holes drilled. maybe drill bit salesman says pecking is bad cause he wants broken drill bits so he can sell more drill bits
1) drill bit new used less than 20 minutes
.
2) 10" deep horizontally drilled .375" dia hole, feeds and speeds in normal range with shorter drill depths has 99.999999% success rate per 100,000 holes
.
3) programmed to enter 4" deep .375 dia pilot hole at low rpm once in hole rpm goes higher and a G1 at feed given to 10" depth, when done spindle shuts off and it pulls drill out.
.
4) as often happens at high or low feed and 500 different in between feeds and speeds on a deep hole no coolant getting to drill tip and flutes hard packed with chips. no coolant ever getting through to the drill tip coolant. so drill breaks 9" into hole. happens about 5 to 20% of time based on data from last 100,000 holes drilled
.
5) 10 hours labor into machining part, broke drill often takes longer than 10 hours to remove. the drilling without pecking maybe trying to save 5 to 10 minutes drilling. at end of year broken drills taking at extra 50 hours of labor per year (removing broke drills or remaking parts) that was trying to save maybe 5 hours per year by not peck drilling
.
6) data from last over 10,000 parts and easily over 100,000 holes show peck drilling if done carefully like slowing rapids and having machine stop rapids and go into feed at least 0.1" away (parameter setting) to stop slamming into chip bur sticking up at hole bottom at rapids speeds. having peck not have drill tip come fulling out of hole but stay a 1" in hole to save drill tip whipping hurting drill tip on hole rentry with drill tip..... the failure rate peck drilling carefully is less than 0.01% the failure rate of trying to deep drill without pecking
.
7) just a observation that not pecking when deep drilling has cause 10x to 100x more problems than peck drilling. so who is one who figured not pecking is better when data from last 100,000 holes says other wise ?? .....and yes over 500 different speeds and feeds tried. failure mode 99.999% of time is hard packed chips clogging flutes increasing turning resistance til drill breaks. many materials like cast iron do not flow chips through flutes any better at higher or lower feeds from data on last 500 different settings tried
.
just observing its one thing to talk theoretical peck drilling is bad, its another thing dealing with broken stuck in hole drills and remaking parts which normally are causing 100x more problems based on last 100,000 holes drilled. maybe drill bit salesman says pecking is bad cause he wants broken drill bits so he can sell more drill bits