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Author Topic: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?  (Read 20893 times)

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Offline khalid

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Looks to be working well :)

Think I would be spinning slower and feeding harder though.

Hood
Yaa.. The system is working well now... Following is my experience:

1- The HSS drill failed on the Second hole... I kept the RPM 800 and G73 cycle with Peck 6mm.. It simply toasted;) Flood coolant was On... 2min/hole

2- The second bit is used was Carbide, It ran for 30 holes and then suddenly break into 3 pieces... Again G73 peck cycle but with 2.5mm peck... 2 minute/hole

3- I then used  HSCO drill and with G83 Cycle, lost it after 38th hole with 2.5mm peck... Coolant on.. 7minute /hole

4- Keeping all above experience in view, i again used HSCO drill but at this time G83 with 2mm peck (DOC) and after each 15 holes i sharpen the drill.. For this i added tool change command after each 15 holes in my Gcode.. i slightly changed the Gcode for downtime...
The above strategy went very good and i did above 100holes without breakage... 5minute /hole

5- I have HSS drills available, so i tried the same G83 cycle with them with 2mm peck and sharpening after each 15 holes..and i did 50 holes without loosing HSS drill.. 4.5min /hole

I have done 224 holes in 16.8 hours.

Offline khalid

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Started building new Spindle and its houseing.. The Spindle is off AISI 4140 hardened to 55HRC... and now it require grinding... The Vertical column is also in fabrication phase.. I will get red of complete Radial drill except the Cross-slides..
The New column is very sturdy..

Offline Hood

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New spindle etc looks like it will be a big improvement :)

I have never had much luck with carbide drills in stainless, 8% cobalts  are best for me,  you have to feed them hard as any rubbing at all and the stainless work hardens very quickly, I would probably spin an 8mm at about 600rpm and feed at 40mm/min in 316. I also try and make sure the coolant is pointed directly into the hole with a strong jet.
Hood

Offline khalid

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Hi Hood ,
I have now to enlarge these 8mm holes to 9.5mm... Now I am going to do it with Standard Drill Cycle (G81).. Is it right? what mm/min i should travel the drill and at what RPM?
Regards

PS:
or anyother suggestions for 9.5mm holes.!!!

Offline khalid

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Here is the updated pictures of spindle housing being machined on Boring Mill and the completed tube sheet.

Offline Hood

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Khalid,
Thats not a great situation to be in, I think the drill will grab a lot due to the small amount you are going to be removing, I think I would try an endmill to enlarge rather than a drill.

Looks like you have some nice big machines :)
Hood

Offline khalid

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Hi Hood,
Today I finished the tubesheet drilling with final hole size 9.5mm..
You were right the drill grabed long swarf ..However I Gcoded to stop the machine after each 5 holes... Following was my strategy..

Spindle RPM: 400 RPM
Feed: 3 IPM
Peck Cycle: G73 with 3mm per peck
Time to complete One hole: 1minute 5 seconds

I drilled all the holes within 5Hours.. You can see the video in the following youtube link..
http://www.youtube.com/watch?v=FH2X_W2MHBY

Offline Hood

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Looks to be working great :)

Hood

Offline khalid

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Today I just experimented drilling on Multilayered baffles of the exchanger. Each single  baffle has a thickness of 3mm, total baffles in One Bundle= 18. Total thickness to drill= 55mm. We have used 8mm HSS drill and after TEN thorough holes the HSS drill was sharp as new.

Offline Hood

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Do you machine the outer profile at a later stage? If yes, how do you do that, lathe?


Hood