Pm 940v

[nighthawkFmobil]

Hi @nighthawkFmobil

WRT to the gib. The big end, (top), of your gib looks typical. The small end (bottom), of the gib which is chewed off is similar to mine, but not as bad. As I said mine did not work at all as the screw pushes it into the way making it a clamping force, not a gib. I made a washer with a finger sticking out to catch the gib end. At the time I was cutting some thin aluminum and it was clamped to my backer board anyway so I just used this Al. It was thin, so I may have used to layers in the gib hole. I cannot recall. However, something harder would work better.

Just for you..... I have a bridge... for sale...

I will attach two files for you that may be useful. One is just a drawing of the washer. The other has Gcode. In addition I will through in another gcode which you can simulate if you want.... it for the instrument panel I was making. I made 4 washers at the time out of this thin Al. The made the tab a bit large as I figured I was going to have to file by hand to get it to fit anyway. So the ID was to fit the bolt and the OD was to fit the hole where the gib screw head was receding into. That hole on the 940 was not well defined (sloppy) so I made it as large as I could and have it still fit. The finger on it sticks out and I just tried to make it larger than needed so I could file it down. I was actually cutting a much more complex panel plate with lots of odd shaped holes and just put the gib washer on the end of the Al that I was cutting. I put a holding tab on the circle edge so that the part would not tear out as it was being cut.

I will stick the Gcode I wrote for the process, but it is way overly complex and may not make a lot of sense to you.... as I said I was cutting other parts at the same time. I was using a 2mm diameter end mill. Anyway, I was taking very small cuts so the thin parts would not get bent as they came loose or curled out of the cut material. I will also attach my Mach3 Gcode text files for these cuts and another for the washers..... which you can simulate to see what it looks like. This gcode looks extremely complex, but maybe you can extract something that you might want to run. The reason for the complexity is that I actually did the parts design in Visio, then wrote a program in Excell that allowed me to shift and rotate any individual part to a location in the X-Y plane and places its holding tabs at any angle. The Excel program automatically generated the Gcode, which I then made into a text file. Some of the parts also had flats on the circles as well as the holding tabs.... so the Excell was used to calculate where the cutter went from making a circle to making a straight line or where the tool was lifted to make the holding tab... as a function of how the part was shifted in X-Y or rotated. Anyway, I will share it, along with the Gcode for the washers. Maybe you can run the washer Gcode just as it is written, but you may have to make a leap of faith!!!

Not to be incomplete, I will also attach a 4th file, which should be the same as the 12Circles-2Rects.... file but with comments. When I had put all these comments in the file it would not simulate in the MillWizard software as it had too many characters! I cannot recall if it would actually run in Mach3. The MillWizard simulator is actually a lot different from the actual Mach3 software.

Dave

Yes, thanks for sharing. Love to see what otger people are up to with drawings and g code. Had no idea people used excel to generate g code. Ill have to look inti that more.

 

[B2]

Hi @nighthawkFmobil
Yes, I have used Excel several times. I use it to do the calculations and then organize things. I usually use variables when I do and one of the problems with the Mach3 is that the available variables are not well defined. It is a bit of a guessing game. Most all of the 9000's, a large fraction of the 8000s, and 7000s are available. You can see what I used in the gcode. You can put the line numbers, GCommands X, Y, Z etc in the columns and then a row becomes a line of G code. Each column has meaning and then in another column you grab each of the cells that you want in the final line and use the CONCATENATE command to gather the cell entries, add spaces, commas, ), etc.
Example: CONCATENATE(B178,C178," ",D178," ",E178," ",F178," ",G178," ",H178," ",I178," ", J178," ",K178," ",L178," ",M178," ",N178," ",O178," [",P178,"] (",Q178,")")

The cell entries can be numbers, text, etc. What ever makes sense in G-code. However, in Excel the numbers will carry too many digits etc for Gcode so you need to make those entries the right number format by limiting the number of digits with a command like rounding.
Example: =+ROUND(E77,4) .

If you decide you want to try your hand at something like this I suggest you start with a simple object.

In the example code that I posted, I took one page to make an object shape. Based upon another page which carries the info for the particular object: shape, size, X-Y location, tab locations on the object, number of tabs, tab widths, flats on a circle, rotation angle etc would feed into the particular page where the characteristics were used to manipulated the values math wise. This way one set ups multiple pages to handle multiple objects. this page generates the G-code text for that particular object.

Then I use a macro system to gather up the various G-codes for each object into a set of G-codes. In this page subroutines are used to call each object to be cut via the main program.


All of this seems rather complex and is, but once written one can create sets of objects with different parameters, location, size, etc. pretty fast and can easily change these if you want a different layout. So on the Gcode I posted for you you can quickly see the set of routines for each of the objects being cut out. But only the final results are in the posting. If you really want to dig deep I could send you an Excel program... but it may take longer to figure it out than to write one for your self.

Obviously, if you are only doing one object this might be a lot easier to just draw it in a CAD package that automatically generates Gcode. Of course if you want to change one object this is not too hard if you only have one object, but if you have a lot it gets to be a little more tedious.

Dave

 

[B2]

BTW @nighthawkFmobil

If you are interested, you can see the panel I made using the posted Gcode, or one similar to it, in my posting on the VFD conversion. Photo 15a. I think. Note the 12 circles and 2 rectangles for the instrument cluster switches, digital meters, lights, screws (at the corners) etc. With a Gcode simulator you can compare the picture to the simulation. The 940 nodding and back lash has prevented me from even trying to do any small size engraving. So the lettering on this is from a label (tape) making machine.

More Pictures 3

Dave

 

[nighthawkFmobil]

BTW @nighthawkFmobil

If you are interested, you can see the panel I made using the posted Gcode, or one similar to it, in my posting on the VFD conversion. Photo 15a. I think. Note the 12 circles and 2 rectangles for the instrument cluster switches, digital meters, lights, screws (at the corners) etc. With a Gcode simulator you can compare the picture to the simulation. The 940 nodding and back lash has prevented me from even trying to do any small size engraving. So the lettering on this is from a label (tape) making machine.


Dave

I was just anout to ask. What is your 940 good at?

 

[nighthawkFmobil]

I just got done putting everything back together. My initial finding is the same result. Man, i put a lot of work in but owell. More testing in the next couple of days. I have a starrett square on the way to check squareness of xy

 

[nighthawkFmobil]

I guess at this pount this has become somewhat of a journal.

After last nights post and this morning before work i did more test on the column and head. Overall the test were good. Im finding my magnetic indicator holder could be playing a factor. Im also finding my nod to be a heck of a lot less. Makes me winder if the gib wasnt seated properly.

After cleaning everything up and getting it back together its definitely running a lot more smoothly. For right now i have the gibs tight but im not sure its neccessary. Probably going to do ankther 40 test lol then see if i can get the spindle to table within acceptability. Fingers crossed, i could use some hope right about now. Glad i got some.

I think im realizing there's multiple factors with a machine like this when trying to achieve decent repeatability as well as smooth operation(how it feel manually) and function, aside from how nice and tight of a fit the dovetail/gib matches up. B2 you were right about the gib not being a clamping force. I learned much about that. Is it acceptable to put loctite on gibs? Not really confident enough in my adjustment but i could see it being helpful. Maybe a washer could have same effect in my situation

 

[Christianstark]

I guess at this pount this has become somewhat of a journal.

After last nights post and this morning before work i did more test on the column and head. Overall the test were good. Im finding my magnetic indicator holder could be playing a factor. Im also finding my nod to be a heck of a lot less. Makes me winder if the gib wasnt seated properly.

After cleaning everything up and getting it back together its definitely running a lot more smoothly. For right now i have the gibs tight but im not sure its neccessary. Probably going to do ankther 40 test lol then see if i can get the spindle to table within acceptability. Fingers crossed, i could use some hope right about now. Glad i got some.

I think im realizing there's multiple factors with a machine like this when trying to achieve decent repeatability as well as smooth operation(how it feel manually) and function, aside from how nice and tight of a fit the dovetail/gib matches up. B2 you were right about the gib not being a clamping force. I learned much about that. Is it acceptable to put loctite on gibs? Not really confident enough in my adjustment but i could see it being helpful. Maybe a washer could have same effect in my situation

When you say put loctite on the gibs, what do you mean specifically? Just curious, as I am still waiting for my machine, which is a Taiwanese machine.

 

[nighthawkFmobil]

When you say put loctite on the gibs, what do you mean specifically? Just curious, as I am still waiting for my machine, which is a Taiwanese machine.

Loctite in the gib adjustment screws sorry. One of my gibs had a cracked or reallly sloppy made screw head seat. It turns the gib into more of a clamping force instead of something that holds it in place so i cant tighten down on it much. Loctite could hold it in place

What mill did you order?

 

[yota]

why not have PM get you some new Gibs? any way to drill and tap a for larger gib screw where the bad threads are? I have read that the grainy structure of the chinese cast steel makes it difficult to tap. maybe a helicoil?

 

[Christianstark]

Loctite in the gib adjustment screws sorry. One of my gibs had a cracked or reallly sloppy made screw head seat. It turns the gib into more of a clamping force instead of something that holds it in place so i cant tighten down on it much. Loctite could hold it in place

What mill did you order?

Ordered an 833TV. The ship it is on is sitting offshore near Seattle. Should dock today, and then it will be on a train for a few weeks en route to Pittsburg.

Why don't you use the mill to clean up the screw seat a bit, so it has better engagement? Yes, I do recognize the silliness of my suggestion. Just adding some levity to an annoying situation you are in. . Do the jib adjusting screws line up properly in the gib dimples? Is one off center? I was thinking the gib adjustment screws would have a jamb nut so lloctite was not necessary. You may consider swapping out those screws for a better set screw from McMaster? Would rounding the tip slightly help it read in the gib better, and apply a more uniform force?

Edit - I re-read the situation. The casting is the actual issue with the gib screw, and not the screw itself? I would talk to PM BEFORE you attempt to re-tap or helicoil that so they can advise, and you don't blow your warranty. Can you post a picture of the casting area where the gib screws go?