[wcarrothers1]

Well I've been running my R2V3 for a while. Most of the playing I've done have been just streight moves or segmented moves to make turns. Of course due to limited memory using arch moves is a good thing to save program space.. but for some reason and I yet to figure out my machine does not seem to do them right.

In short when cutting the archs the turn ends up streighter then it should. Like the lower right turn on that part should be a circle but it cuts the corrner off in a shallow arc.

I run the same code in mach on my other mill and it does not apear to cut the arch short.

Please see the pics below and segment of Gcode I'm trying to run for my part.

1 pic of the part
1 pic of the plot of the part from NCPlot back plotter
and the Gcode.

Thanks for Any help to understand what is going on.



'Bridgeport'
'Cut StockPart no ramps'
N4G70G75G40G17G90
N5G0X0.0Y0.0T12M6
N6S12000M3
N7G0Z0.7874
N8G0X0.1250Y1.1050Z0.0500
N9G1Z-0.0270F5.0
N10G1Y1.1055F10.0
N11X0.1244Y1.1173
N12G3X-0.6200Y1.7752I-0.7092J-0.0524
N13G3X-1.3644Y1.1173I-0.0352J-0.7103
N14G1X-1.3650Y1.1055
N15Y1.1050
N16Y0.5455
N17Y0.5450
N18X-1.3647Y0.5365
N19G3X-0.6200Y-0.1252I0.7095J0.0486
N20G3X0.1247Y0.5365I0.0352J0.7103
N21G1X0.1250Y0.5450
N22Y0.5455
N23Y1.1050
N24G1Z-0.0540F5.0
N25G1Y1.1055F10.0
N26X0.1244Y1.1173
N27G3X-0.6200Y1.7752I-0.7092J-0.0524
N28G3X-1.3644Y1.1173I-0.0352J-0.7103
N29G1X-1.3650Y1.1055
N30Y1.1050
N31Y0.5455
N32Y0.5450
N33X-1.3647Y0.5365
N34G3X-0.6200Y-0.1252I0.7095J0.0486
N35G3X0.1247Y0.5365I0.0352J0.7103
N36G1X0.1250Y0.5450
N37Y0.5455
N38Y1.1050
N39G1Z-0.0810F5.0
N40G1Y1.1055F10.0
N41X0.1244Y1.1173
N42G3X-0.6200Y1.7752I-0.7092J-0.0524
N43G3X-1.3644Y1.1173I-0.0352J-0.7103
N44G1X-1.3650Y1.1055
N45Y1.1050
N46Y0.5455
N47Y0.5450
N48X-1.3647Y0.5365
N49G3X-0.6200Y-0.1252I0.7095J0.0486
N50G3X0.1247Y0.5365I0.0352J0.7103
N51G1X0.1250Y0.5450
N52Y0.5455
N53Y1.1050
N54G1Z-0.1080F5.0
N55G1Y1.1055F10.0
N56X0.1244Y1.1173
N57G3X-0.6200Y1.7752I-0.7092J-0.0524
N58G3X-1.3644Y1.1173I-0.0352J-0.7103
N59G1X-1.3650Y1.1055
N60Y1.1050
N61Y0.5455
N62Y0.5450
N63X-1.3647Y0.5365
N64G3X-0.6200Y-0.1252I0.7095J0.0486
N65G3X0.1247Y0.5365I0.0352J0.7103
N66G1X0.1250Y0.5450
N67Y0.5455
N68Y1.1050
N69G1Z-0.1350F5.0
N70G1Y1.1055F10.0
N71X0.1244Y1.1173
N72G3X-0.6200Y1.7752I-0.7092J-0.0524
N73G3X-1.3644Y1.1173I-0.0352J-0.7103
N74G1X-1.3650Y1.1055
N75Y1.1050
N76Y0.5455
N77Y0.5450
N78X-1.3647Y0.5365
N79G3X-0.6200Y-0.1252I0.7095J0.0486
N80G3X0.1247Y0.5365I0.0352J0.7103
N81G1X0.1250Y0.5450
N82Y0.5455
N83Y1.1050
N84G0Z0.0500
N85G0Z0.7874
N86G0X0.0000Y0.0000
N87G0X0.0Y0.0M25
N88M02

[cut more]

Bob,
I have a boss 8,
I think your trouble is due to the bottom arcs coming in towards the center kind of like a rounded W (exagerated I know)What do you use for cad/cam software? If you are using Bobcad I have a post for that at home, I could send you a re-posted file tomorrow.
I know the boss controls will accept radius command too. That saves a bit of precious space.You could try that. I think with the radius command you can do a 180 degree arc but I will check that when I get home.

Is the geometry supposed to be continuous arcs? If so there is a problem there.I back plotted the cam file to bobcad and the arcs have different center points.

Hope that helps
cutmore

[wcarrothers1]

The Gcode produced from a post processor built up for Vcarve to make files for the bridgeport. I've played with the different parts of the post (that I understand) to get it working as good as it does now. But comming here because I'm still missing something but can't really blame vcarve or anything.

b.

[wcarrothers1]

Just confused seeing when I open that Gcode in something like the NCPlot back plotter (like in the picture) the part paths look ok. If I output using the Mach arc's post the code is the same (with the exception of the header G's) and path looks right.

so just confused I guess. and figured perhaps I was missing some header g command to put it in the right mode for this or something simple like that.

b./

[wcarrothers1]

For example perhaps I sould be in G74 multi quadrent circle input off rather then G75 circle input on. But don't really know what all that means. And not really clear in the manual but think 75 should be on or default.

b.

[cut more]

Bob,
I will check my settings when I get home. I am leaving work for the day.
Try this file. Z zero to be the top of the material.

:666
N2G0G17G30G40
N3G45G70G72G75
N4G90G96
T1M6S3000
M3
N6X0.125Y1.105Z0.5
N7G1X0.125Y1.105Z-0.02 F.5
N8X0.1244Y1.1173Z-0.02 F10.
N9G0X0.1244Y1.1173Z-0.02
N10G3X-0.62Y1.7752Z-0.02R0.7112
N11G0X-0.62Y1.7752Z-0.02
N12G3X-1.3644Y1.1173Z-0.02R0.7111
N13G1X-1.365Y1.1055Z-0.02
N14X-1.365Y0.5455Z-0.02
N15X-1.3647Y0.5365Z-0.02
N16G3X-0.62Y-0.1252Z-0.02R0.7112
N17X0.1247Y0.5365Z-0.02R0.7112
N18G1X0.125Y0.545Z-0.02
N19X0.125Y1.105Z-0.02
N20G0X0.125Y1.105Z0.5


I will check back tomorrow,
Cutmore

[wcarrothers1]

Thanks for the Gcode.. I'll give it a try and guess the new G's in your headder will be added to my post processor..

Thanks!!..

b.

[cut more]

The G codes in the header I understand are
G0= rapid, G17= x,y plane, G40= tool radius comp. cancel.
G70= programming in inch, G75= something with the arcs( I forgot to look in the manual last night,Sorry)
G90= programming in absolute coordinates.
I will look up the rest, or if you have the manual you could look them up.
I know every control can have different interpretations of a Gcode so the Boss8 & 10 could be different but I doubt it.
Hope that helps,
Cutmore

[Verfur]

G75 I think was is full circle ability. Hum may have to do with end piont tollerance.
can you post a drawing of your part with dims and origin? Just at a glance somthing looks off in the centers of the arcs to me. May be my eyes who knows

[cut more]

Verfur,
I saw the same thing, the arc center points are not the same. The geometry from backplotting looks like a rounded w on the bottom.
We will see how he made out when he comes back.
Cutmore

[wcarrothers1]

The archs are as symetrical as they can be far as I know...

I could post the vectors drawn..

The code given above gives an error message on the boss screen after the tool change. I altered it as one of the feed rates was .5 and that. But the error said something that sounded like it didn't understand one of the subscripts (I think it said) of course there isn't enough room on the screen to give a complete sentance error and of course I didn't copy it down.

Far as the manual goes all the Gcodes in the header look like they would be acceptiable. And the manual does have R commands for circle interpolation.

If I take my drawing and move it to have the part zero in the lower left corner of the part rather then lower right the squashed parts of the arch move to the other corners of the part.

Just kinda fustrating seeing the same code runs an arch and path just fine under Mach. so maybe my machine is just showing it's age? I'd hate to think that because otherwise it runs everything else I do as good as I could ask.

Maybe I'm missing something simple but have checked the programmer manual and stuff and think it should work.

I agree that the centers of the arcs should be/could be the same since the part is symetric but I'm not seeing the squasing when I view it in the back plotter that I see when the part is run.

Anywho.

b.

[cut more]

Bob,
I just looked at the file I sent and this time I changed the 2 arcs to a single arc. Try this and let me know if this works. If so, then maybe it is something with the original file that the Boss just didn't want to do.
:667
G0G17G30G40
G45G70G72G75
G90G96
T1M6
G0X0.125Y0.6198Z0.5
G1X0.125Y0.6198Z-0.02 F1.
X0.125Y1.0302Z-0.02 F10.
G3X-1.365Y1.0302Z-0.02R0.745
G1X-1.365Y0.6198Z-0.02
G3X0.125Y0.6198Z-0.02R0.745
G0X0.125Y0.6198Z0.5
Hope this helps,
Cutmore

[wcarrothers1]

I'll for sure try it. Thanks.

I did look at where my orignal gcodes were placing the arc centers and like some have said they don't look like their placement makes any sense to me. So probably fooling the heck out of the bridgeport to.

Thanks.

b.

[wcarrothers1]

Also Vetric got back with me on how to update the post processor to do absoloute output for arc centers (which is why the code was not working most likely as some noticed the arc centers are not right)..

Anyway hopefully that is now all figured out. But I'll keep you posted once I try it to be sure.

b.

[wcarrothers1]

Just to give us all an idea where the old and new arch centers were loacated with the post processor change see the 2 pics..

The colored circles mark the arc end location and the center.

I'm sure all can see why the bridgeport was so confused.

b.

[wcarrothers1]

That did it.. Thanks to all that helped..

Now I have the bridgeport busy kicking out these little things.

Although I need to figure a better way to hold them down..

but anyway.

b.

[cut more]

Bob,
Glad you got the Bport figured out.

On how to hold those parts, I use vacuum on some of the jobs I do. You just make a fixture that has a channel (made with a ball nose) a tiny bit inside the part. Place a rubber gasket in the channel. A couple of channels in between the gasket, and connect a refrigeration vacuum pump and you would be amazed at how much hold down you have!
It is nice for repetitious parts cause you can put locating pins or even mill a pocket the part fits in.

Cutmore

[wcarrothers1]

Ya I have to get on the vac hold down bandwagon. Sooner or later I'll have to get me a vacume setup.

Actually this piece has a bolt hole in the middle so if I locate that first I can bolt it down and that might also work well.

b.