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Back Spotface Question

Are you using the standard nc sequence? If you are you are using a boring bar to do this cycle. I should just nove over when it gets thru the hole and back bore. You might see this cut work in vericut. What type of cut do you want to do? I have been through this and I went a reverse spot facing tool. There are three ways to do this type of hole 1: bacdkboring like you are doing here. 2: A keyway cutter milling thru the hole on the backside. 3: Use a back spot facing tool. The first one is an inxpensive fast way to do this hole if your operators understand the way it works. The second type is low in cost for the tool but cycletime is not as good. The third one is good for long run production IMO. The tooling cost is high.


Cncwhiz
 
I need to do it the way I am showing because of the way we are fixturing the part. This is the standard practice for back spotting in our shop.


When I post this sequence I only get the linear moves shown in the graphics generated in Pro/E. There is no circular motion.
 
If you want circular interpolation, you will have to do it with a "Trajectory" sequence. You will have to set the tool orientation before the plunge, and turn on the spindle after it is through the part. This will output the code that you need, but the tool will visually dive through the model because Proe thinks the tool is turning at all times. I do this a lot. Doesn't look pretty on the screen, but I get the desired tape output.
 
appinmi - could you download my file and send me an example of what you are talking about? Thanks
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CNCWHIZ - I don't understand your question. We are using a custom made tool similar to a boring bar. We want the tool to enter the hole, move over, and sweep a circular path to create the large back spotface feature.
View attachment 2286
 
I only have Wildfire, I cannot read in a Wildfire 2.0 file. But I will try to create something similar so you can see how I do it.
Edited by: appinmi
 
Soddyboy,


What does your gcode come out like? You should post it so we can look at it. I have used this sequence on fanuc controls. Pro does not always show the tool path correctly. Allan, can he save his mfg file to a nutral format? Do you have tool parameters on this tool?
 
Well, here it is. You have to sketch the tool, which makes it look like a T-slot cutter. If you play an NC Check, you will see the tool plunging through the part. But, if you are really using a back boring tool, and it is orientated correctly, it won't cut through the part when machining. As you can see, I use "GOTO' points and "CL Commands" to achieve the desired results. I even added cutter comp for you. There is also the tape file that I posted.


2006-05-17_104113_backspot.zip
 
Allen,


I think that he is using a back bore cycle. The kind that you use a boring head, with the spindle offshift over after the hole plunge,turn on the spindle, back bore the hole re-orient the tool and stop the spindle, shift over again retract. You knowlike a "G76" cycle on a mill with a fanuc control?
 
I know all about the back bore cycle, (G76). But I think he is sayingthat the tool is not the diameter of the back spotface, therefore it has to interpolate to achieve the correct diameter. There is no "cycle" that will do that automatically. All I did was give him a way to achieve the desired results.
 
That is why I was asking him what style he wants to use? Why don't you build a custom cycle instead of all the cl words in the trajectory like you showed me? What will the boring tool work like doing a circle cut? The side relief is not built to do that?





Cncwhiz
 
Allan is correct. The tool is not large enough to do a back spotface. I have been working on doing it the Allan shows it in his example. If there is a way to do a custom cycle that I could use I would like to know how to do that too.


Thanks to both of you.


Soddyboy.......
 
Well, here is a custom cycle that I made to do this task. It is the best I could do with the time allowed. The "cut" is not parametric. The radius the tool follows is directly from operator input. I could not select the diameter of the spotface as a reference. I didn't add any tool motions to this cycle since you cannot define the proper tool to see the results anyway. So, here goes:


View attachment 2292


View attachment 2293


View attachment 2294


View attachment 2295


View attachment 2296


View attachment 2297


This cycle will output cutter comp. Positive or negative radius determines the direction and the "G41/G42" output. Attached is the "workcell" with the custom cycle, a post processor with the FIL file required to make the moves, a text file explaining what you see in this post, the end result tape file, and the "test" manufacturing files I used to make this cycle work.


2006-05-21_164006_backspot.zip


Good luck;
 
Allan,


I defined the cycle as you have shown and get notool motion. When I look at your cycle example there is no tool either. I have been playing with the tool motion by adding cycle points and modifyers. Am I on the right track? Thanks
 
Why in the world do you want to show the tool motion since you cannot define the correct tool? The tool motion is only a graphic display and has nothing to do with the tape code. If you were to add the tool motions, it would gouge into the part. Not a good representation of the cut! When I play the tool path, with the tool defined as an endmill, the tool shows up at the "goto" points at the top of each hole.


Did you load my example manufacturing file? Did you look at the tape code?
Edited by: appinmi
 
I did not mean tool motion graphic display. I meant motion in the tape file. The tool was only moving to the start point for each hole. I finally figured out that our post processor was the problem. I am working on editing it now. I did look at your example and it helped a whole lot. Thank you very much.
 
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