CNCzone.com-The Largest Machinist Community on the net!



Home Page Mark Forums Read Today's Posts My Replies Classifieds Reviews Photo Gallery Web Links Share Files Advertise With Us Ad List
Go Back   CNCzone.com-The Largest Machinist Community on the net! > MetalWorking Machines > Haas Mills


Haas Mills Discuss Haas machinery here!


This forum is sponsored by:

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Ban this user!
Old 09-30-2010, 10:05 AM
 
Join Date: Mar 2010
Location: USA
Age: 28
Posts: 35
DruMor is on a distinguished road
Drilling deep holes in cast iron

In the very near future I will be machining grey iron castings that have 25/32 dia holes drilled 5.5" deep thru the part. I have been machining these parts for the past 3 years without TSC and have to make many small pecks to get the iron out and it takes forever. The machine has just been equipped with TSC, installed by Haas. What kind of feed/speed increases are possible since I now have TSC? Any ideas on if I will still have to peck drill with larger pecks or if I can drill straight thru?

Machining will be with a VF-4 and HSS TSC drills.
Reply With Quote

  #2  
Old 09-30-2010, 12:18 PM
HuFlungDung's Avatar
Moderator
 
Join Date: Mar 2003
Location: Canada
Posts: 4,825
HuFlungDung is on a distinguished road

Question: in your previous drilling operation, why the many small pecks? That is a pretty fair sized drill and you should be able to use one of the Haas drilling cycles to drill the first 2.5 inches without a peck, then about a 1" peck after that. It should not take forever. You should be feeding the drill at about .02" per revolution to keep a fluffy swarf that doesn't pack into the flutes too much, but instead augers up well. You might want to temporarily adjust the peck return height parameter if you do a lot of this, so that your drill doesn't come back down hard onto a few chips in the bottom of the hole. Just make sure your peck depth is longer than the peck return height or you'll be there forever

There may also be some benefit to grinding the sharp edge off the drill lips, turning it into a neutral rake tool, instead of positive rake (following the helix angle of the flutes). Grind a flat as wide as your feed in IPR.

With TSC, I suppose you can drill non-stop, that is the whole idea of it.
__________________
First you get good, then you get fast. Then grouchiness sets in.

(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
Reply With Quote

  #3   Ban this user!
Old 09-30-2010, 01:02 PM
 
Join Date: Mar 2010
Location: USA
Age: 28
Posts: 35
DruMor is on a distinguished road

I kept the pecks small because it seemed like if I made them deeper I started to have problems with the drill slamming into chips on the way back into the hole. Also I wanted to make sure I kept the end of the drill cool. In the G83 drill cycle, I had a I1. J.187 K.6 for my peck depths. Sounds like between the peck depth and FPT I wasnt pushing it hard enough before. Right or wrong, I usually seem to start way slow with feed/speed and sneak up slowly because the only thing I hate worse than scraping a part is tearing something up.

My boss and I did discuss this morning possibly changing the peck return parameter you mentioned. Our thinking was it would give the coolant a little more time to flush out the hole.
Reply With Quote

  #4  
Old 09-30-2010, 02:45 PM
HuFlungDung's Avatar
Moderator
 
Join Date: Mar 2003
Location: Canada
Posts: 4,825
HuFlungDung is on a distinguished road

Too light of a feed in cast iron will make too much powdery swarf, such that the drill flutes are not able to auger them out of the hole. That is why you need to push the feed to make a heavier chip that will come up. But with TSC, it is really a moot point.

I would still 'doctor' the cutting edges as I describe above. The drill will be less apt to hog in on heavy feed, and the neutral rake edge will last far longer than a conventional drill tip, giving you much less headache so far as premature seizing of the drill in the hole, due to dull corners.

I cannot say I'd like machining cast iron wet because of the sludge it makes, but I'd suspect that poor sludge handling may be a result of poor sump design. The old mills with a sump in the base, of course had no ready method of cleaning the crap out, so cast iron was machined dry to keep the sump clean.
__________________
First you get good, then you get fast. Then grouchiness sets in.

(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
Reply With Quote

  #5   Ban this user!
Old 09-30-2010, 04:12 PM
 
Join Date: Mar 2010
Location: USA
Age: 28
Posts: 35
DruMor is on a distinguished road

I know exactly what you mean about wet cast being nasty to clean out. I try to get the coolant drain hosed and scraped out well every night after I run iron so it doent turn into a concrete blob in the coolant drain shoot. Lying on my back digging the crap out of there isnt fun

I know we have had a drill ground before like what you describe for a manual drilling operation in this same part. A normal drill liked to grab real bad.

Thanks for your advice!
Reply With Quote

Sponsored Links
  #6   Ban this user!
Old 09-30-2010, 04:14 PM
Cmailco's Avatar  
Join Date: Aug 2010
Location: USA
Posts: 136
Cmailco is on a distinguished road

Using a drill specifically designed for cast iron will save you a lot of grief. I have a client who I've totally sold on the Guhring RT100R, getting roughly 25% better tool life than with the previous tooling in SG cast iron automotive components.

You really need a good setup for these drills though. Less than .001 TIR, and at a minimum, soluble oil through the tool. The 'best' method is in using neat oil, like Blaser Vascomill, but at a minimum, 10% mixture soluble. We're running these drills at ~230-300 sfm in SG, depending on the depth. .012-.024 inch/rev depending on drill size. Consult specifics with Guhring if you decide to go that route.

Best regards,
Chuck
__________________
The Manufacturing Reliquary
http://cmailco.wordpress.com/
Reply With Quote

Reply




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Cast Iron Zumba Casting Metals 6 01-22-2009 03:50 PM
Drilling deep 1/2" holes? lukaslouw General Metalwork Discussion 10 07-29-2008 09:08 PM
deep drilling small holes in aluminum Fremont Dave General Metalwork Discussion 13 11-25-2007 01:03 AM
deep drilling 2mm holes kesparate General Metal Working Machines 9 09-15-2007 11:57 PM
Drilling deep holes. HSM Joe Machine Problems, Solutions , Wireless DNC, serial port 7 05-13-2003 12:14 PM




All times are GMT -5. The time now is 03:45 AM.





Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2012, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO
Template-Modifications by TMS

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361