Re: [Emc-users] Square corners With G41/G42
2011/3/26 Chris Radek : > On Sat, Mar 26, 2011 at 02:31:47PM +0200, Viesturs L??cis wrote: >> >> At least for me it worked correctly in the same way as You said - >> compensation is applied during the first move, regardless, if that is >> G01 or G02/G03. For best results, please test it and report here :) > > Yes, EMC supports an arc lead-in; I can't speak for any other > controls. Arc lead-in can be very useful, especially on an inside > contour. I would say that they not only can, but actually they are very useful :) I _always_ use lead-in and lead-out moves. Sometimes they are just a few mm long, but still. And only case, when those lead-ins and outs are not arcs, is rectangular outer contour, all other cases and especially for _all_ inside contours I am using exclusively arc lead-in and lead-out moves. I think that straight lead-in and the corner, where it meets the actual contour creates more visible mark than a gradual approaching of the actual path as it is with arc lead-in. I have seen results of waterjet cutting, where the burn point is right on the contour and I hate the way it looks, so I think that for plasma and waterjet a lead-in is a must, lead-out is optional. Viesturs -- Enable your software for Intel(R) Active Management Technology to meet the growing manageability and security demands of your customers. Businesses are taking advantage of Intel(R) vPro (TM) technology - will your software be a part of the solution? Download the Intel(R) Manageability Checker today! http://p.sf.net/sfu/intel-dev2devmar ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Square corners With G41/G42
On Sat, Mar 26, 2011 at 02:31:47PM +0200, Viesturs L??cis wrote: > > At least for me it worked correctly in the same way as You said - > compensation is applied during the first move, regardless, if that is > G01 or G02/G03. For best results, please test it and report here :) Yes, EMC supports an arc lead-in; I can't speak for any other controls. Arc lead-in can be very useful, especially on an inside contour. -- Enable your software for Intel(R) Active Management Technology to meet the growing manageability and security demands of your customers. Businesses are taking advantage of Intel(R) vPro (TM) technology - will your software be a part of the solution? Download the Intel(R) Manageability Checker today! http://p.sf.net/sfu/intel-dev2devmar ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Square corners With G41/G42
2011/3/26 Les Newell : > > SheetCam will generate excellent tool center line paths. It handles nesting > of parts within each other correctly and automatically works out which side > to compensate. As I have a number of customers complaining due to the lack > of G41/G42 support I decided I had better do something about it. > But how does it handle open lines? I had one customer, who wanted to cut out animals from plywood for small kids and open lines inside the outer contour were part of the design. > >> in my shop we have used small offsets in EMC2 for a long time >> we have had no issues of resulting incorrect geometry from entry or exit >> motion > > If you look at the docs on radius comp you will see that if you don't > have a lead in, the first move will become the lead in. The start of the > move will be un compensated and the end of the move will be fully > compensated. I don't know what happens if the first move is an arc. > At least for me it worked correctly in the same way as You said - compensation is applied during the first move, regardless, if that is G01 or G02/G03. For best results, please test it and report here :) > Which is why I am adding G41/G42 support. If SheetCam knows about the > offset it can generate the correct tool paths to allow for it. In some > cases it does mean that parts of the original drawing may be optimized > out but the generated tool paths will be completely legal for EMC or any > control as long as you don't specify a larger radius in the control than > you specified in SheetCam. I think that making amount of optimization to be depending on the max kerf width, specified by user, is very useful idea! I just would recommend testing it more than 6 times with different designs, because I managed to get that "concave corners, gouging needed" error also on outer corners, where it did not make sense to me. > The difference is that if SheetCam knows about the offset then it can > make sure that for instance inside corners always have a big enough > radius to allow for the tool without any warnings that you will gouge > the part. My conclusion was that G41/G42 compensation works correctly for inside corners, which are created by two straight lines, so creating rounded corner is not necessary. The problems start, when these straight lines are shorter than diameter of the tool (or even more, if that is very sharp inner corner - for example, in a star contour). So I think that instead of making rounded corners it would be enough to clean up code and make sure that there are not many small straight lines. Viesturs -- Enable your software for Intel(R) Active Management Technology to meet the growing manageability and security demands of your customers. Businesses are taking advantage of Intel(R) vPro (TM) technology - will your software be a part of the solution? Download the Intel(R) Manageability Checker today! http://p.sf.net/sfu/intel-dev2devmar ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Square corners With G41/G42
> in my shop we have used small offsets in EMC2 for a long time > we have had no issues of resulting incorrect geometry from entry or exit > motion If you look at the docs on radius comp you will see that if you don't have a lead in, the first move will become the lead in. The start of the move will be un compensated and the end of the move will be fully compensated. I don't know what happens if the first move is an arc. > if you have artistic designs and generate tool centerline code with a lot of > small linear (and possibly circular) moves then EMC2 and its radiusing of > the outside and inside corners will be problematic at best and unworkable at > worst Which is why I am adding G41/G42 support. If SheetCam knows about the offset it can generate the correct tool paths to allow for it. In some cases it does mean that parts of the original drawing may be optimized out but the generated tool paths will be completely legal for EMC or any control as long as you don't specify a larger radius in the control than you specified in SheetCam. > if you change to part geometry code (offset by the tool radius) you will > have a different program but you will still encounter the same problems with > the cutter comp > the same amount of change ie .002 inch > with centerline code total adjustment is -.002 > with geometry code total adjustment is still -.002 even though > the number for a 1/4 cutter is .123 instead of .125 > both will not work for the same reason The difference is that if SheetCam knows about the offset then it can make sure that for instance inside corners always have a big enough radius to allow for the tool without any warnings that you will gouge the part. > I ,too, would like to have the choice of using this feature or not > I have requested this option and argued this point more than one time (to no > avail YET) :) > > I want 5 axis cutter comp - with this 'feature' enabled 5 axis cutter comp > is not workable - with this feature disabled then 5 axis cutter comp would > be possible My brain hurts trying to think about 5-axis comp. I assume you could only use it with a ball nosed cutter. Thinking about it, surely kinematics would have to add the comp, not the interpreter. The interpreter doesn't know about the kinematics of the machine so it doesn't know the cutter orientation. Actually adding squared corners isn't that difficult. Instead of calculating the angles of the two lines to add an arc you simply find the intersection of the two lines. The difficult bit is finding someone motivated enough to do it. I am afraid I don't have a plasma or waterjet so I don't have a lot of incentive to do it myself. Unfortunately my spare time is rather limited. I am only just finishing off my EMC controlled lathe now and I started that about 2 years ago... Les -- Enable your software for Intel(R) Active Management Technology to meet the growing manageability and security demands of your customers. Businesses are taking advantage of Intel(R) vPro (TM) technology - will your software be a part of the solution? Download the Intel(R) Manageability Checker today! http://p.sf.net/sfu/intel-dev2devmar ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Square corners With G41/G42
2011/3/25 Les Newell : > With plasma and waterjet cutting the kerf width (cut width) varies quite a > lot as the > nozzle wears so radius comp is useful. But it has to be a hell of a length for one job to wear out waterjet's nozzle (I assume that plasma torches last even longer) or that has to be extremely precise work to account for changes in wear during a single file, but I do not think that anyone would do that with waterjet or plasma because of taper and other reasons. I understand that situations, where some kind of parts are produced in large quantities and thus the same file is ran again and again that can be an issue, but for these cases one can afford spending some more time to ensure that code works correctly with G41/G42. My experience is that in the beginning I wanted EMC2 to handle kerf width with G41/G42 command. I ended up with a "concave corner, need to gouge" error in some files, so I have ended up with my CAM application dealing kerf width. And if CAM app can do it correctly and as flexible as EMC2 (at least my CAM application allows to change the side of the compensation or turn it off for each particular line in the drawing) then there is no difference. Actually I now prefer to do it in CAM application, because I can see on the screen, if the side of compensation is set correctly. It sometimes gets tricky, when a part is nested in the scrap material inside another part - that can confuse those programms. So my conclusion - make sure that Your CAM app does it perfectly and Your customer will not have a reason to look for other options (like G41/G42 commands) to do the same. Viesturs P.S. Les, I sent You private e-mail 5 days ago. Could You, please, take a look at it? -- Enable your software for Intel(R) Active Management Technology to meet the growing manageability and security demands of your customers. Businesses are taking advantage of Intel(R) vPro (TM) technology - will your software be a part of the solution? Download the Intel(R) Manageability Checker today! http://p.sf.net/sfu/intel-dev2devmar ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Square corners With G41/G42
in my shop we have used small offsets in EMC2 for a long time we have had no issues of resulting incorrect geometry from entry or exit motion if you have artistic designs and generate tool centerline code with a lot of small linear (and possibly circular) moves then EMC2 and its radiusing of the outside and inside corners will be problematic at best and unworkable at worst if you change to part geometry code (offset by the tool radius) you will have a different program but you will still encounter the same problems with the cutter comp the same amount of change ie .002 inch with centerline code total adjustment is -.002 with geometry code total adjustment is still -.002 even though the number for a 1/4 cutter is .123 instead of .125 both will not work for the same reason EMC2 does not know or care how big the tool is or isn't EMC2 calculates a radiused corner based upon code geometry and offset value I ,too, would like to have the choice of using this feature or not I have requested this option and argued this point more than one time (to no avail YET) :) I want 5 axis cutter comp - with this 'feature' enabled 5 axis cutter comp is not workable - with this feature disabled then 5 axis cutter comp would be possible -- dos centavos -- Enable your software for Intel(R) Active Management Technology to meet the growing manageability and security demands of your customers. Businesses are taking advantage of Intel(R) vPro (TM) technology - will your software be a part of the solution? Download the Intel(R) Manageability Checker today! http://p.sf.net/sfu/intel-dev2devmar ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Square corners With G41/G42
I have had a couple of customers try to use small offsets but they were never happy with the results. Offsetting a center line path has two problems. First of all the lead in will be incorrect. EMC expects an explicit lead in move when using radius comp. If you don't provide this move then the first cutting move will be incorrect. The second problem is that SheetCam does not know about this offset so it does not allow for it. If the input geometry is very complex (usually artistic work) you can end up with a lot of very short moves. If you add offsets to these moves you can get gouging and overlapping paths. The likelihood of problems is not very high but it is there. To be honest the square corners aren't a big issue. It would be a nice feature to have but very few if any other controllers allow for square corners. Les On 25/03/2011 17:17, Stuart Stevenson wrote: > > you can still use G40/G41/G42 with a tool centerline program > you would just use small numbers for the offset value > -- Enable your software for Intel(R) Active Management Technology to meet the growing manageability and security demands of your customers. Businesses are taking advantage of Intel(R) vPro (TM) technology - will your software be a part of the solution? Download the Intel(R) Manageability Checker today! http://p.sf.net/sfu/intel-dev2devmar ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Square corners With G41/G42
On Fri, Mar 25, 2011 at 11:18 AM, Les Newell wrote: > Yes, corner looping makes a big difference but in tight nests corner > loops can waste a lot of space. As a worst case, imagine cutting out an > array of square parts. The corner loops would result in a big spacing > between the parts. I am in the process of adding G41/42 support to > SheetCam and was wondering how to handle this type of corner. Currently > SheetCam generates the tool center line which means it has total control > over the tool path but you can't use radius comp. With plasma and > waterjet cutting the kerf width (cut width) varies quite a lot as the > nozzle wears so radius comp is useful. > > Les > you can still use G40/G41/G42 with a tool centerline program you would just use small numbers for the offset value -- dos centavos -- Enable your software for Intel(R) Active Management Technology to meet the growing manageability and security demands of your customers. Businesses are taking advantage of Intel(R) vPro (TM) technology - will your software be a part of the solution? Download the Intel(R) Manageability Checker today! http://p.sf.net/sfu/intel-dev2devmar ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Square corners With G41/G42
Yes, corner looping makes a big difference but in tight nests corner loops can waste a lot of space. As a worst case, imagine cutting out an array of square parts. The corner loops would result in a big spacing between the parts. I am in the process of adding G41/42 support to SheetCam and was wondering how to handle this type of corner. Currently SheetCam generates the tool center line which means it has total control over the tool path but you can't use radius comp. With plasma and waterjet cutting the kerf width (cut width) varies quite a lot as the nozzle wears so radius comp is useful. Les On 25/03/2011 10:20, Alex Joni wrote: > Not currently, this would probably come from CAM for best results. > I've seen some CAM systems that allow adding outside loops for sharpest > corners (so you go past the endpoint, then do a loop in the scrap material, > and enter the endpoint with the new cutting direction). > > Regards, > Alex -- Enable your software for Intel(R) Active Management Technology to meet the growing manageability and security demands of your customers. Businesses are taking advantage of Intel(R) vPro (TM) technology - will your software be a part of the solution? Download the Intel(R) Manageability Checker today! http://p.sf.net/sfu/intel-dev2devmar ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Square corners With G41/G42
Not currently, this would probably come from CAM for best results. I've seen some CAM systems that allow adding outside loops for sharpest corners (so you go past the endpoint, then do a loop in the scrap material, and enter the endpoint with the new cutting direction). Regards, Alex - Original Message - From: "Les Newell" To: "Enhanced Machine Controller (EMC)" Sent: Friday, March 25, 2011 12:16 PM Subject: [Emc-users] Square corners With G41/G42 >I have a question about G41/G42 tool radius compensation. Normally when > you have an outside corner while using radius comp, an arc gets added > around the corner. While this is the best technique for milling/routing > and turning it isn't ideal for plasma/flame/waterjet cutting. With jet > cutting the jet exit point trails behind the entry point. In a straight > line this does not matter but when you go around a corner the trailing > exit point tends to cut the corner. If the corner is squared off this > gives more opportunity for the jet to catch up making the corner sharper. > > Is this possible in EMC? > > Les > -- Enable your software for Intel(R) Active Management Technology to meet the growing manageability and security demands of your customers. Businesses are taking advantage of Intel(R) vPro (TM) technology - will your software be a part of the solution? Download the Intel(R) Manageability Checker today! http://p.sf.net/sfu/intel-dev2devmar ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] Square corners With G41/G42
I have a question about G41/G42 tool radius compensation. Normally when you have an outside corner while using radius comp, an arc gets added around the corner. While this is the best technique for milling/routing and turning it isn't ideal for plasma/flame/waterjet cutting. With jet cutting the jet exit point trails behind the entry point. In a straight line this does not matter but when you go around a corner the trailing exit point tends to cut the corner. If the corner is squared off this gives more opportunity for the jet to catch up making the corner sharper. Is this possible in EMC? Les -- Enable your software for Intel(R) Active Management Technology to meet the growing manageability and security demands of your customers. Businesses are taking advantage of Intel(R) vPro (TM) technology - will your software be a part of the solution? Download the Intel(R) Manageability Checker today! http://p.sf.net/sfu/intel-dev2devmar ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
