machine cutting larger than mpc

[jab73180]

Hey all. I made a project this weekend and had some troubles. I did the project 3 times before it would carve right. The first time it didnt carve in the center where i wanted it. The second time it carved the project great but it was to big on the width of the project. the third time it carved right because i put a bigger board in.

I designed a sign 12" x 18" in designer. It would carve fine the 12" way, but it cut it almost 19" wide. thats all well in fine after i put the 20" board in on the third attempt.

I am using a sled that is 14 1/4" x 38 1/2". i have 3 1/2" of each end thats is solid and rails naturally down the edges. I have tape all along the bottom of the sled for the tracking roller and for grip. I use 2 sided tape to secure the board to the sled.

I think i have fixed the centering issue with a new board tracking encoder. Luckily i put a stock order to LHR a few days ago.

My question is what is causing the enlarged project?

My firmware version is 1.171, do i need to upgrade to the newest?

Do i need a new memory card?

The last 2 projects i did came out the same so does that mean the machine is reading the mpc wrong?

Any help will be good. Thanx in advance.

[Digitalwoodshop]

Jason,

I would load the latest Designer.

Confused with your end result... A Picture would help....

Remember if you select to center on the Board and you put in a bigger board for Width it will give you some messages... If you get problems in length centering it could be because the board lost contact with the brass roller.... Masking Tape helps....

I use place on End rather than center on board as it will measure the board twice and possibly skip.... And get it wrong...

It is sometimes good that after you have all the layout done for the project that you turn off all the Centering and Restraints. If you put in a bigger board sometimes it causes your project to go bonkers as one of the restraints is pulling a object to center and messing you up.

AL

[jab73180]

i dont have the projects because i sent them to the customer so they could see what happened. the sign i designed was an oval. the first one i did was 2 inches to the left. the second one i did was centered but it cut the oval out to big, but everything was proportioned. i was kinda thinkin it was a bad download or my memory card is dieing on me. does that sort of thing happen? i dont think the board lost contact, i can see where the roller grips the masking tape. thanx for the help Al, i knew i could count on you.

[jab73180]

so now i am having a problem with my machine not centering left to right on project. my latest project was 3/4" to far to the left shown here in this picture.....44918
i didnt check top to bottom but i think it is right.

44919This is a picture of the sled i use. The board in the sled is 12" X 18" so the sled itself is 14 1/2" X 30" or so. the base of the sled is 3/4" plywood and the edges are just 3/4" X 3/4" pine. the ends are 3/4" X 3" pine. i used 3 strips of tape on the bottom of the sled for grip and board tracking. I use double sided tape to attach the project to the sled.

44920In this picture i show how i mark the center of the project board and line it up with the centerline marks of the sled. all the centerline marks have been double checked.

I have put a new board trackin encoder in but it didnt help i guess. i have carved a lot of the same size and type of projects with this setup with no problems. im stumped on this one. any help will be appreciated.

[fwharris]

Jason,

Have you checked your head pressure?

Are you using any out feed supports?

[AskBud]

This is just a stab in the dark!
You stated your end pieces are 3". You need at least 3.5", and some pro's suggest 4".
Let us know how your next test works.

Also, include the MPC without the dragonfly, so we may see the placement.
AskBud

[DickB]

Post your mpc.

[jab73180]

This is just a stab in the dark!
You stated your end pieces are 3". You need at least 3.5", and some pro's suggest 4".
Let us know how your next test works.

Also, include the MPC without the dragonfly, so we may see the placement.
AskBud

I double checked the end and it was 3.5", but just to be on the safe side i glued a 1" strip to the inside of the end.
i didnt keep the mpc but i do have another test i can do to see about placement and i will post that mpc when the glue dries on my sled.



Jason,

Have you checked your head pressure?

Are you using any out feed supports?


The total length of the sled is 38", i just checked. do i need out feed table supports for that??

i do need to check head pressure, but would that cause a centering problem?

[AskBud]

When you do your next test, note all the chosen options you use in the machine and post them as well.
AskBud

[fwharris]

The total length of the sled is 38", i just checked. do i need out feed table supports for that??

i do need to check head pressure, but would that cause a centering problem?

Jason,

My thinking on the outfeed tables and head pressure was, if the head pressure was low and with the total weight of your sled (3/4" ply+rails and project board) it could have slipped on the brass roller. When the sled come out from under the pressure roller it could have slipped/tilted a bit causing the tracking problem..

[AskBud]

Extra rollers are always good to consider on long or heave stock/sleds.
However, in this case I think that since you have no problem with the basic shape of your oval the problem is not a tracking issue. If you had a flat spot on the oval it would be a different matter!
That's why I asked for the list of chosen options.

I presume that you centered your design, the wood, and used the option to center on board option However, I'd like to have your list from the next test.
AskBud

[jab73180]

Extra rollers are always good to consider on long or heave stock/sleds.
However, in this case I think that since you have no problem with the basic shape of your oval the problem is not a tracking issue. If you had a flat spot on the oval it would be a different matter!
That's why I asked for the list of chosen options.

I presume that you centered your design, the wood, and used the option to center on board option However, I'd like to have your list from the next test.
AskBud

Yes I center everything. I know some people use place on end. How does that work?

[AskBud]

Place on end, also, works well. You just need to be consistent with how you mount your wood on the sled for either one of the methods to be applied.

When using a sled I use the "center" method, and when using just a board (longer than the needed +7) I "place on end" just to save as much good wood as possible.
AskBud

[jab73180]

well i thought the problem was with my sled but it wasnt. i had gaps on the non roller side of the sled that i never filled because i wasnt going to use that side of the sled on the roller side. some how i did use it that way because i could see the divots the brass leaves on the side i didnt want to use, darn shop gremlins. so today i carved an ash board without the sled and got a centering problem and a sizing problem, so that rules out the sled problem. the project came out the perfect height, but it was 1" to far to the right. i centered it on the virtual board so i dont know what i am missing. this must be a measuring problem the machine has. i did change out the brass roller to the new design, do i have to calibrate it??? also the project in designer was 25" and the carving came out 26". which leads me to believe the machine isnt measuring right. and also i forgot to tape the roller side of the bottom of the board. that could be part of my problem but i am having trouble with and without tape so i dont know where to go after this. thanx in advance.

[AskBud]

well i thought the problem was with my sled but it wasnt. i had gaps on the non roller side of the sled that i never filled because i wasnt going to use that side of the sled on the roller side. some how i did use it that way because i could see the divots the brass leaves on the side i didnt want to use, darn shop gremlins. so today i carved an ash board without the sled and got a centering problem and a sizing problem, so that rules out the sled problem. the project came out the perfect height, but it was 1" to far to the right. i centered it on the virtual board so i dont know what i am missing. this must be a measuring problem the machine has. i did change out the brass roller to the new design, do i have to calibrate it??? also the project in designer was 25" and the carving came out 26". which leads me to believe the machine isnt measuring right. and also i forgot to tape the roller side of the bottom of the board. that could be part of my problem but i am having trouble with and without tape so i dont know where to go after this. thanx in advance.
What is the size of your design, and the size of your board? How did you answer the sizing prompt? Did it turn out somewhat wider as well as longer?
AskBud

[jab73180]

ok so i just got home. i have enclosed a mpc of my project. i made the virtual board just large enough for my pattern. my real board is really 8' long. this is how i answered all the prompts that i got in the order i got them.....

stay under rollers...yes
keep original size...yes
how to center board...on length
cut board to size...no

the height on the real board came out perfect but the length came out to long. i have another board going through right now and it was going to start about 4 inches off. i raised the head and moved the board where it should be and continued. this board is long so an inch or two wont matter. i taped the roller side of the bottom of the board but something is still wrong.

when i changed one of the bearings on the Y truck is when everything went haywire.
so what i have done is...

changed 1 Y truck bearing everything was cutting longer than MPC
changed brass roller sensor to the new updated roller....that didnt change anything.

so this is a pretty weird deal, any help would be great.

[AskBud]

With an 8' length, I hope you were using extra supports rollers starting about 3 feet from the unit! I see your design board is 30".
I fail to see where the "Y" would have any effect on the "X" measurements.
Is the "O" ring still in the proper place on the brass roller?
AskBud

[jab73180]

With an 8' length, I hope you were using extra supports rollers starting about 3 feet from the unit! I see your design board is 30".


i held the ends of the board just for measurment. the carving was in the center of the board so i didnt need supports for that.



I fail to see where the "Y" would have any effect on the "X" measurements.

i dont see the connection either bud, but thats when it started.




Is the "O" ring still in the proper place on the brass roller?

certainly is, here is a picture...http://i1085.photobucket.com/albums/j429/jab73180/My%20Shop/Carvewright/IMG_20110620_210549.jpg


also here are some other pictures of the finished project....


http://i1085.photobucket.com/albums/j429/jab73180/My%20Shop/Carvewright/IMG_20110620_210558.jpg
you can see it came out a lil less than a inch longer, but the width came out right on.


http://i1085.photobucket.com/albums/j429/jab73180/My%20Shop/Carvewright/IMG_20110620_210608.jpg

http://i1085.photobucket.com/albums/j429/jab73180/My%20Shop/Carvewright/IMG_20110620_210619.jpg

so what other ideas do we have????

[jab73180]

wow pretty good pictures from my phone, kinda large but better for the older gents!!

[AskBud]

First, your pictures show a very rough carve edge. I can see the same rough edge on portions of the text as well. What chuck are you using? Is it ,properly, holding the bit? What carve speed option did you apply to the card?

Second, I changed the board design to 25.5 to see how much off you really are.

Third, Hand held is not the same as external rollers. the extra overhang will tend to bow the board, which will tend to lift the board off the brass roller somewhat. Do you see a difference in text spacing anywhere along the carve?
AskBud45306

[Digitalwoodshop]

I would run the Calibration.... Something I have never done....

I would blow the sawdust from the black plastic area of the brass roller. It could prevent the roller from rising enough to get a good grip on the wood.

Masking Tape?

AL

[jab73180]

Bud I am using the rock chuck. I figured the fuzzyness was just from the ash. And that was a new bit.

Al I usually use dust collection but I had to put my machine in a different spot in my shop due to the length of the project. I did use masking tape (which I forgot to remove and the customer isn't gonna like it when he runs it through his drum sander.) I did use tape on the bottom.

I will try the calibration when I get home and Thanx.

[jab73180]

Bud I am using the rock chuck. I figured the fuzzyness was just from the ash. And that was a new bit.

Al I usually use dust collection but I had to put my machine in a different spot in my shop due to the length of the project. I did use masking tape (which I forgot to remove and the customer isn't gonna like it when he runs it through his drum sander.) I did use tape on the bottom.

I will try the calibration when I get home and Thanx.

[jab73180]

so i have been busy with my calibration. it was measuring 1.3745" shorter than the board. I got it now to .5815" shorter but it wont let me go any further. i have a calibration range error.

the default reading is 890.430 and the new reading is 874.555. it wont let me go lower than that. do i just need to shut it off and let it set for the night and try again tommorrow??

thanx for the help.

[jab73180]

so it pissed me off when i got the calibration within 3/8", which still isnt close enough. i sat down and thought about and decided to put the old sensor back in and give it a try. i put the old one in and presto, problem solved. i dialed it in to .008" and called it good.

my problem must have been when i ran the sled the wrong way in the machine, i freaked and thought it was the machines fault when it was my own. that still doesnt help the fact that the new board tracking sensor is messed up. a call to lhr tommorrow will hopefully rectify that. thanx to everyone that helped.

[DickB]

I was looking into the rubber traction belts option and if you go that way there is a new o-ring for the brass roller as the belts are a bit thicker. I wonder if you got the wrong size for your machine?

[liquidguitars]

One thing that will mess-up your measurement is a rolled up sandpaper belt normally at the keypad side, I cut .50" off each side on the belts without exception. Where you place the sled is important and how you ask the CW to layout. I never center but "place on corner" the CW will look at the front edge of the sled and not calculate a math error based on centering.

Regarding sled, I normally use 4" or bigger tails on my sleds then load the tail under the board sensor to get a clean y measurement. My layout in designer will also reflect my sled, you will not see any of my MPC not include the sled dimensions this will remove some of the guess work and probably keep you from hitting a screw and damaging the Carvewright.