Thanks everyone. Millman I will have a look at the files, thanks. I will try a couple more settings thismorning just to make sure I havn't forgotten something and if I still have problems I will put the file on the FTP site. While it sounds like it may be a post problem, I am wondering if it has something to so with the compenstaion direction setting, (left or right). I do not fully understand the meaning of this setting when it comes to 5 axis surface machining. I know that when 2D contouring etc it changes the side of the line you are on but maybe someone could describe its function in surface machining. I would have thought that the computer would have looked at the complete radius of the tool and compensated to that regardless of whether it is apporaching from the left or right?

Have alreeady selected the appropriate comp surfaces the comp to surfaces. Problem is that it looks exactly right when backplotting and verifying. It is only when you machine the part that problems show up.

Sorry I havn't replyed to your questions earlier but have been away for a day. The Thermwood post I am using is from CNC Automation. I have verified the ref tool length with a simple program where I machined a simple contour path from above, then rotated the B axis 90degree so that it came in and machined the same surface that was cut with the contour path and it was perfect. Also accuratly measured the length from pivot of B axis with machine cooridnates and DTI gage. I am therefore 100% sure the tool length is correct. I have worked out what is actually happening now. The part is a simple top third of a sphere with a flat plane at the bottom. It is a flow5axis path radiating from the top centre and tool is remaining normal to surface at all positions (no axis limits set or anything like that). Tip is selected for Tip comp. The path it generates is therefore touching the surface as it goes radially from the centre stopping by 1/4" above the flat comp surface plane at the bottom (as it should because it is a 1/2" ball nose cutter). SO everything looks fine here. What it accutally cuts is it is touching at the top as it should but as the tool moves down the tool path, it starts digging into the part and stopping 1/4" above the bottom plane. At this bottom point the lowest tip of the ball nose tool is on the tool path and therefore has cut into the part by the tool radius. Therefore also stopping 1/4" above the plane since this is the tool path stop point. So the bottom tip of the tool is following the toolpath and ignoring the radius of the cutter as though it was referencing to the top tool plane even though the tool motion remains normal to the surface. I am thinking that it could be something to do with the T/C plane settings for the path and will try changing them. I hope this decribes the problem clearly. If not I could put the file on the site for someone to have a look at. You might have to tell me how to do this. Thank you.

I am having a great difficulty getting the desired result from my 5 axis tool paths. My machine is a Thermwood 67. I have machined a test part to learn on, using 3D pocket tool paths and have programed some 5 axis toolpaths which should run over the 3D surface and just touch the already machined surface. I am doing this as verification just to check I have all the 5axis parameters correct. The result I get is miles different from what it should be. Trouble is that when I backplot and verify everything looks fine but the actual result is up to half a cutter diameter, different but not in any pattern to suggest that I am compensating to the wrong side etc. Any help would be most appreachiated since I have spent all day playing around with different settings(mainly the comp settings and tip and centre settings as I thought that it was most likely to be these) but get all sorts of diffenrent results none of which are correct. (but they all look correct in the backplot, which is a bit of a worry). I am not sure what to do next. This newsgroup is my only help since I have found that even though we have paid Mastercam maintenance, it doesn't actually entitle you to any help. Thank you.

Thankyou for all the infomation. I will enter some values and experiment with different settings and see how I go.

I am just starting to post files to our Thermwood 67 machine that we have just installed. When posting it prompts for some fields. A couple of them I don't understand and was hoping someone with a similar machine can help me out. It asks for 'Enter ref tool length'. What does this mean? I thought that it used the values that are set up through the tool library and therefore was already defined. Each tool would have a different ref length I would have thought? Also it asks for 'rapid height for tool/op changes'. Is this the height it moves to to change tools (flip dual end spindle over) and is measured from machine home position. Also don't really understand the part offset choices of G92 G51 G52 G53. Thanks.

I am not sure how to create a tool library. I would like to set up a library with just the tools that I own so that when creating a tool path and I choose 'select tool from library' it goes to my library. Maybe someone can help me out here. It is probably really simple but I am new to Mastercam and can't quite seem to work it out. Thankyou.

I played around with the depth controls and got it working well. Because it maintians the shape of the tool path within the boundry all the way out to the highest depth, it spends a bit of time cutting air initially but I guess you can't overcome this without having a seperate toolpath first with a smaller boundry. Thanks

I have set up a cplane 30degrees off vertical and created a rough parrallel toolpath to this plane for machining the curved side of the part. It works fine however, because the stock starts off as a square block sitting on the machine table, when I create the rough path relative to the 30degree plane it starts its cuts from where it first sees the surfaces and not from the corner of the stock, therefore there is a large triangle of stock missed. How do I remove this stock? Can I tell it to start cutting from the corner of the stock rather than where it first sees the surfaces to machine? It would appear that it doesn't regonise the stock. Note that I setup the jobsetup using bounding box with the cplane orriented to top as it would be with the stock positioned on the table ready to be machined.

Thankyou for the advice. I will try it out and see what happens. I thought that I would use some 3d tool paths referenced to angled planes to remove excess stock leaving a small amount of material on the surfaces and then use a 5 axis flowline or multi surf to finish machine. I presume this is the correct approach.

Hi. I am new to mastercam and new to the forum and situated down in New Zealand. I have a 5 axis Thermwood 67 and am trying to work out how to rough out a deep steep sided part in 5 axis. You can only go so deep when approaching from the top before the head hits the part. I want to be able to tilt the tool and rough out the sides of the part. I understand that all the 3D tool paths are avalable in 5 axis but am unsure of how to do this. I guess I want use a surface rough operation with the tool referenced to an angled plane and for the tool path to regonise the stock boundary so that it doesn't cut air for any length of time. Thank you. Hopefully someone can help me out. I am running Mill 9.1 sp2 Level 3