Unwanted Ramping of Text

[Sharkdan]

I have owned my CNC Shark 16 x 24 about a month and have zero cnc experience this may be something i did but I don't know what:

First, out of the box, started it carved the text right to left and mirrored - readable if you held it to a mirror. I took the gantry off and put it back on backwards, facing away from the stepper motor, and it now carves words correctly. Only problem is it ramps every letter at the end of each pass when using Quick Engraving. There is no option to ramp in Quick Engraving. Using a v-bit makes it look very obvious. Sent some .crv files to a Vectric tech who said there is nothing wrong in the g code.

This is getting tiresome. Why did I have to turn the gantry 180 degrees and why does this thing ramp?

I have re-set the card in the back of the controller many times but it doesn't cure the problem.

Please help!

[martin54]

Don't know what control software the shark uses so can't tell you how to put it right but turning the gantry round the other way wasn't a smart move, I would put it back round the right way & get on the shark forum and ask questions on there.
The problem is with the x & y axis being set up the wrong way round & you should be able to alter that in the machine control software. I could tell you how to do it in mach3 but don't know what control software the sharks use.
Best bet as I say is to register with the shark forum & ask on there, they will probably be able to help with most machine based problems you may have better than this forum can.

[martin54]

Quick search on the shark forum found this:

http://www.cncsharktalk.com/viewtopic.p ... try#p16144

Not read it all but if it doesn't help fix your problem it's a good starting point for finding something that does.

[Sharkdan]

Thanks for the reply Martin54!

I took a look at the post you linked to, it might be what I need. Later today or Sunday, I will turn the gantry around and go through the steps outlined on that thread. Can't hurt anything as long as I write the numbers down before I start, right?

All the best!

[Sharkdan]

I followed the directions in the Shark Forum post and did a couple of test cuts. The first time the router assembly tried to take x+ off of the gantry!

I used control E, & 787 to access the setup numbers and changed the negative on X to positive.That seems to have fixed it as last night I carved a couple more signs with out any trouble. Keeping my fingers crossed.

Thank you!

[martin54]

Thanks for updating the post, will hopefully help others who have a similar problem, did a bit of reading & it would seem that rotating the gantry seems to be the way a lot of shark owners fix the problem, seems ridiculous to me that there isn't more help from the sellers of these machines, having rotated the gantry in order to be able to cut you have invalidated any sort of warranty the machine comes with.

[Sharkdan]

I do not understand what happened overnight but things are screwed up again this morning.

Y axis is backwards when control E, 787, is set to factory settings.

Text is mirrored, meaning you would have to hold it up to a mirror to read it.

Plus, I have the text ramping problem back - meaning the bit goes up and down while carving, miss-shaping the letters.

Anyone have any good ideas?

Frustrated here.

[Karen_W]

Sharkdan - this may have exactly zero to do with your problem but check to make sure you're using the correct post processor first.
Then check to make sure you have your X and Y leads hooked up correctly.
Also, if you haven't yet, register for the forum and post your problem there. The members are all Shark owners and someone may have had a similar problem with a solution for you.

[martin54]

Send it back for a refund lol

Checking your using the correct PP is always a good idea when things don't go right, when you say the z axis goes up & down does it do that literally as it is cutting or does it shart at one depth & get lower as the cut goes on? If it gradually cuts deeper that could be due to lost steps.
Have you tried any other types of toolpath other than the quick engrave, say like the profile or vcarve toolpaths? If you have do you get the same sort of results.

Not sure why the settings would return to factory default unless there is a save changes button you have overlooked, might also be that you need to save each change individually before moving on to the next one.
I would definitely be asking these questions on the shark forum, best place to ask really as they will all have the same brand machines.

[Sharkdan]

Thanks for the advice guys, I really appreciate the thoughts and help. I am going to take this to Shark forum for sure.

But the good news is, I changed the y axis setting in "control E" to positive, left x negative, and left Z positive. That fixed the mirror thing.

I caused the router to try to go off the gantry by using an older file that had the z zero in the wrong corner. My bad.

So I am back to the ramping problem. It goes smoothly down to start, say, .125. Then the router starts a slow ramp up but the computer screen shows .125 until it pulls completely up for the next move.

So that is where I am now.

Thank you, thank you!

[martin54]

Firstly I would delete any files you are unsure of to prevent the same happening again with the x axis, good practice if you have to redo stuff anyway lol.
Have you checked the Post processor is correct for your machine? Haven't used the quick engraving toolpaths myself so can't comment on them or how they work. Have you tried other toolpaths & what results did you get with them?
Have you checked that the table is flat & that the spindle is set up square to the table? Are you sure the material you are trying to engrave is flat & that your not bowing it at all when you clamp it?

[Sharkdan]

As for the Post processor, I am using what Rockler sold with the machine.

Bowed stock is not the problem as I realize bowed material would be problematic - I plane everything that is not perfectly flat before it goes on the table. And, I am careful to check it after clamping too.

As for the table not being flat, the ramps are all over the signs I cut, some top of text some bottom. There is not a gradient over the length which would give that impression. It is individual letters.

I have not tried a different toolpath. I will later today.

Thanks for the thoughts!

[martin54]

After you have your toolpaths all sorted in vcarve try saving them using the cncshark usb arcs either inch or mm depending on what units your machine is set up for obviously.
Does there seem to be any sort of pattern with this z up & down movement or does it apear to be completely random? If you engrave the same text a couple of times are the errors in the same places each time.
What font's are you using? are you using true type or the single line fonts supplied with the program.

[Sharkdan]

Yeah, I am saving them to the arc inch file and can easily load them into the Shark Control panel.

The errors were random I first thought but I put a sign back into place and recut it using the file, bit, zero, and depth. It did what it did before meaning it ramped in the same places and cut over twice the depth on one whole word.

I use a lot of the single line fonts. The one we are talking about is Futura West 1 line. I have used other fonts including true type with the same results though is does better with scripts for some reason. In all cases they are fonts supplied with VCarve Pro.

After talking it over and going through an exhaustive list with Rockler, I requested a new machine. I can't keep my business open and going if I can't fulfill obligations to my customers.

So sometime in the not too distant future, this should all be fixed. But I am not holding my breath.

[martin54]

Well best of luck getting the machine replaced, let us all know how you get on. Yes if you are running a business equipment has to be reliable. Have you got someone who you can sub the work out to until you get your own machine sorted?
I use a local sign company for some stuff that I don't do in house, never had a problem with them trying to steal my customers & works out well for me as I am not turning work away or sending people elsewhere.