post for mach3

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kevinl
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post for mach3

Post by kevinl »

I normally use the post mach2/3 arcs(inch)(*.txt). I have been having alot of troubles with cutting flat bottom pockets with my dyna cnc. Tech support from dyna told me today that i need to have a post with the extionsion .tap instead of .txt

I dont really have a clue if this could help or not.

I will add a picture to show the results of what is supposed to be a flat bottom pocket.Image

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js11110
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Re: post for mach3

Post by js11110 »

Looks like your tool is pushing up? Or your losing steps in Z. As far as *.TAP versus *.TXT- I can't see a reason why that would make a difference. Their both just text files. We have machines at work that can have any extension as long as the Gcodes are correct the machine don't care whether its a .txt, .nc, .ptp, etc.

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kevinl
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Re: post for mach3

Post by kevinl »

I dont know what the file extension would make any difference either. The machine isnt the most rock solid either, but I have looked it all over and cant find anything so loose as to get that bad of results. The machine has servos and not stepper motors and I do not know anything about that end of things. When I paid the extra for servo motors I was under the assumtion they did not loose "steps"??

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Rcnewcomb
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Re: post for mach3

Post by Rcnewcomb »

Do you see the same thing if you choose a raster toolpath rather than offset?
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kevinl
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Re: post for mach3

Post by kevinl »

Thats exactly what I was thinking, I left the material on the machine and cut the same pocket with raster instead of offset and cut just slightly deeper, the results are not what I would like, but they are much better.

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lstovall
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Re: post for mach3

Post by lstovall »

I had that same problem on a lightweight machine though not quite that bad. I started using a down cut bit and that solved most of it.
Marv

kevinl
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Re: post for mach3

Post by kevinl »

Marv

you hit the nail on the head with the lightweight machine. I am really disappointed in the dyna cnc router. I have had problems with it since day one. The biggest problem is that it is just not rigid enough, and they know it. Their tech support is trained to blame everything on software issues or "dirty power" to the machine.

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lstovall
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Re: post for mach3

Post by lstovall »

I don't know anything about a dyna but the problem you are experiencing looks the same as the problem I had. You would be surprised at how much vertical pull and push a router bit has when cutting. You might try a straight bit. I started using a down cut because the table was less flexible than the gantry. Most of the time I will texture the background so the problem doesn't matter so much or even show up. Since I got a much bigger and sturdier router, that has not been much of a problem except when I do not have thin stock clamped down good enough. That seems to be a big factor in whether or not any router cuts as accurately as it can, extra good clamping/vacuum. I've been fooling around with CNC for about five years and have rarely run across much that was a software issue. It may not do what you want it to do but most of it does what it was designed to do or is told to do. I'm sure that sometimes there are some software issues but I sure haven't run across many with the software I use. Also, if there is a software issue with any Vectric products, you can bet that the Vectric team will be all over it in an instant.
Marv

cabnet636
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Re: post for mach3

Post by cabnet636 »

i spoke at lenght about purchasing dyna and a couple of other 8020 bolt together machines, they were seriously overselling the machine and for what i ultimatly needed.

are you using mach or wincnc controller?

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kevinl
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Re: post for mach3

Post by kevinl »

Marv

I even ran the same cutfile twice on the part in the picture, so tool pressure was a non issue the second time around.

Jim

When I was shopping I ran across some information on the net about the owner of Dyna, long story short he had helped a couple guys get 8020 machines up and running that another company had built and they were very grateful. Then he started his own company and After talking with him some I really liked the liniar rails and bearing blocks so I went with them. After the machine was delivered I couldnt get him acknowlege me again, like I metioned above their tech support was horrible right off the get go. As a matter of fact I talked to them this past week and they told me that I would have to pay over $1000.00 a year for them to even talk to me now because my machine is over a year old! They do offer unlimited lifetime tech support for the machines they sell now?? Looking back I should have went with shopbot, they were pretty similar in price and after reading the shopbot forum they have alot of really happy customers.

cabnet636
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Re: post for mach3

Post by cabnet636 »

i know i have steel table camasters!! there is no way the dyna would have not danced on the floor when compared to the machines i have.

jim
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lstovall
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Re: post for mach3

Post by lstovall »

Kevin,

Something else I tried was to make the last cut only about 0.010 to 0.015 deep. If it still gives the same result like that then you definitely have a machine flex problems somewhere or a loose bushing or Z axis or some type of backlash.

Jim,

I am using Mach3 on an EZ-Router. I like the welded table. The table itself is a lot like the CamMaster.
Marv

cabnet636
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Re: post for mach3

Post by cabnet636 »

i did come real close to the ez router, and found brandon to be very forthright in his dealings, the only reason i did not go that route is the same reason as shopbot, i wanted a flat table for nesting without reaching into the machine, i went and saw his new machine and he is well on his way now!!

jim
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CAMaster ATC 508 24/7 http://dropc.am/p/EJaKyl

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lstovall
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Re: post for mach3

Post by lstovall »

Roger that on the side rails. If they had had the scorpion available when I bought mine I would have gotten one, there isn't that much difference in the price for the same caliber machine.
Marv

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Thkoutsidthebox
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Re: post for mach3

Post by Thkoutsidthebox »

I had similar issues to this before. My money is definately on some flex or looseness somewhere in the Y/Z mechanism. In my case it was a combination of the gantry ends, and the the Z carriage itself. You need to look at the entire group of components which can affect the position and stability of the tip of the cutting tool. Start at the gantry mounts on the X rails and work inwards to the carriage, spindle, and down to the tool tip.

Remember, and this is important.....even a 1mm variation at the tooltip can give blatently obvious defects on a workpiece. If you have a .5mm defect in 3 places, thats potentially a minimum of 1.5mm error at the tip, not to mention that the error is often amplified by cutting forces. Does slowing your cutting speed and/or depth of cut WAAYYYY down alleviate the problem to some extent? If so thats an obvious sign of flex/looseness issues.

Is there any movement between the gantry or gantry beam and the end supports?
Can the gantry end supports tilt slightly or up/down on their rails?
Moving inwards, are the Y rails secure on the gantry beam?
Can the Z carriage tilt at all on the rails and gantry?
Can the Z screw move up/down at all when without power and stationary, is there any slack?
If you push/pull against the base of the spindle/router, or the top edge of the spindle/router, can you see the tip of the cutting tool move?
Whats the condition of you spindle and collet?
This is a biggie....is your spindle perfectly perpendicular to the table top? If not (And I've had to fix this problem on two routers) then when using a flat bottom bit, one side of the tools base will be lower than the opposite side, leaving similar marks to these. A very easy way to test for this is to cut some parallel linear paths as if surfacing, if this is the issue, you will see parallel machining mark lines along the surface.

Because there is variation in the depth of the 'grooveing' (For want of a better word) on your pic, I'm inclined to blame a rocking motion at the tool tip as it cuts, this would lead to variations in the depth dependant upon variations in the cutting speed and direction throughout the piece.

Your problem could be one or a combination of these problems. It could be something different, but I'm guessing not. Changing the toolpath strategy would also lessen/increase this issue because the tool will be travelling more often in the direction that the gantry, carriage, spindle etc are stiffer/looser.

Edit: Between the Y and D, and the bottom-left of the A and C, and the middle right of the photo, you can see the variations in depth that I'm talking about. At least the first two of these look like areas where the cutting tool would have changed direction, and we can see the DOC is different at these points.

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