I am trying to make dog holes on my spoil board. I am using a 1/2 endmill. Yes, I checked it and itis within .001. I am asking the gen two machine using victrices Vcarve pro to do a pocket hole of .750 but they come out at .742-.743 my material for the dog fence is .752
I made sure the holes are saved using the journeyman redline inch post processor. Any ideas?
Kind of a long shot, I know, but assuming you are using a pocket toolpath, make sure that you havenât got an offset selected.
nope no offset selected.
A few thoughtsâŚ
- Are the holes round or (slightly) oval?
- Are the pocket walls vertical/plumb?
- Are you adding a final spring pass?
- Have you tried a smaller endmill (1/4") with stepovers/multiple DOCs?
- Have you ever calibrated your axes (i.e., does an MDI X = 600 mm move the spindle exactly 600 mm)?
- I believe you checked for a âstock to leave/offsetâ
Recalculate the tool path and lie about the tool size to make up the difference.
Make sure you are using a conventional (not climb) cut. The climb pushes away from the material resulting in slightly smaller holes.
well i simply told it i want .760 and i got what i needed. now the are a tight fit to the round stock i am using for a fence. .752 hdpe.
My gut tells me deflection is your problem. When your CAD model is 0.75" diameter, the tool may cut a smaller diameter because of deflection. The tool deflects, the spindle and machine deflect a bit, and the material may be pushed away from the cutter slightly⌠all normal in CNC machining.
Itâs pretty common to overshoot the target and try to land on the desired dimension.
To understand if deflection is your problem, try pocketing the hole, then repeat the same toolpath again. If the second toolpath cuts new material, you can be pretty confident the tool was deflecting in the first cut. This is known as a âSpring Passâ - because the tool springs back to itâs natural location when not loaded.
Also could be a worn cutterâŚ
first off, it was a half inch end mill cutter, brand new. and it was not deflection because as I had to tell redline and onefinity, the machine stopped four times forcing me to rerun the program four times from the beginning, and the holes were the same before and after. the first four holes were run four times with no change in hole size. the cutter was within one thousandth of an inch from true .500 but with the way this machine has been having problems. I am beginning to doubt that I will even be keeping this thing much longer. I am just glad I kept my Masso. I have run literally thousands of programs with barely any trouble at all; except ones I caused lol.
I think the term deflection just used universally for the bit moving over under pressure, carbide bits donât bend, they break, the 1F machine is just not that rigid, put a dial indicator on the bit and push, with very little effort it will âdeflectâ several thousands . I have had my Masso machine for several years now and get fantastic results knowing the limitations of the machine.
You looking at an Altmill or something else?
Whats the measure in vectric? And as said climb or cornventual?
Pocket or profile?
Jim right now I am in a sort of holding pattern. Iâve spent too much already to put any more money into a new acquisition and too much to give up and lose this damn thing. I am really really hoping the new grounded HMI will work.
In the meantime just to do âsomethingâ i am purchasing these. Amazon.com: Tamicy 60 Pieces Clip-on Ferrite Ring Core RFI EMI Noise Suppressor Cable Clip for 3mm/ 5mm/ 7mm/ 9mm/ 13mm Diameter/Video Cable Power Cord (Black) : Industrial & Scientific
I am going to put these little âf ersâ on every cable and cord I have in the shop LOL
I bought those, originally for my Machinist with the BB controller, and they worked well.
Might be moot at this point, but in these situations where itâs a repeatable error after rechecking the basic settings â like it sounds like youâve already done â Iâll go in and look at the G code output itself through something like NCviewer.
If the G code is set to create .75 holes, then you know the issue is downstream of your CAM and sender.
-Mark
Every time I scroll and see this topic, I think âget smaller dogsâ. 
LOL good one tommy. what I really did was ask for .765 holes to get an actual .752 hole. 13 thousandths bigger than what the dimensions I requested. the end mill was brand new and withing one thou of true.750 I still have not found a good answer to this problem.