Cutter is pulling up vinyl - Help.

[jmmccann]

Older Roland Cammjet C60. Has always worked fine for me. I noticed some of my cuts were getting a little "grabby" during weeding, so I figured it was time to change up the blade. There was a 45 in there, and since I didn't have another 45, I changed it up to a 60 since I seemed to be doing a lot more fine cutting. Prior to this (with the 45 installed) I noticed I would get a few graphics that would have some corners lifted, but nothing to worry about. When I installed the 60 and cut a new graphic, I found the blade was pulling up a lot of tiny edges and pieces. I've attached a picture.

Any ideas or first steps?

 

[4R Graphics]

3 things come to mind.

first you may need to adjust the blade offset.

second you may need to oil the new blade (or it may have some dirt in the holder).

third you may need to adjust your pressure with the 60 degree blade vs the 45 degree.

Fourth it maybe a combo of all three but I would start with 1 and 3 they are the most likly issues.

 

[PhatGirl]

60 degree blade is for cutting reflective

 

[Mosh]

45 blade for most cutting is fine. Do a new blade, then new cutting strip. When is the last time you changed the strip, I bet that it is.
Pull the blade and made sure there is no crud on the end at the top of the blade making it not turn right.

 

[bob]

...first you may need to adjust the blade offset...

Why is it that the one thing that, once set for any particular flavor of blade, NEVER changes is usually the first thing people advise others to adjust? What is it about the concept of blade offset that seems to befuddle otherwise sensible people? Can there be that many people who are geometrically challenged?

 

[Pat Whatley]

He switched from a 45 degree blade to a 60 degree. Wouldn't that make a difference?

 

[jmmccann]

Thanks so much for all your input. I looked at the vinyl again and noticed that it was tearing slightly at the backing paper so I checked the downforce and discovered it was set to 50!! I have no idea how it got there. So I backed off the blade tip (A LOT) in the holder as well as reducing the downforce. I do know the cutting strip is bad. So I ordered a new one tonight. I am thinking 4R Graphics is right. It's a combination of all 3. After all this, I tried recutting a different graphic and got a much better result. But still a little bit of pulling on the corners. But DRASTICALLY reduced from the original image. I'm also going to oil the blade and possibly replace the blade holder as well. Just to eliminate all the possibilities.

Thanks SO MUCH for your replies. You guys are awesome.

Jeff.

 

[jmmccann]

Mosh. You and 4R pretty much nailed it. The blade also had a slight bit of gunk in it. So, I'll oil it for now until I can get a new one. New cutting strip and maybe a few more adjustments.

Thanks again, You guys are like Jedi masters.

Jeff.

 

[bob]

He switched from a 45 degree blade to a 60 degree. Wouldn't that make a difference?

Shouldn't. The distance from the blade tip to the center of rotation should be the same regardless of the angle of the blade.

 

[4R Graphics]

Bob,

Your right you shouldnt have to adjust the offset even when you change blade angles BUT manytimes I have found that there was something different and had to adjust it (usually just a little).

Also one of the reasons I mentioned blade offset is that it was tearing or lifting the edges which often is because the offset isnt right and it lifts the edge instead of cutting and rotating the blade (and sometimes the blade is sticking out to far (often a newbie problem)).

jmmccann,
Glad its working for you now.

You stated you backed the blade off in the blade holder.
How far was it sticking out?
I use a credit card as a depth gauge the tip shouldnt stick out more than about the thickness of a credit card.

 

[bob]

Your right you shouldnt have to adjust the offset even when you change blade angles BUT manytimes I have found that there was something different and had to adjust it (usually just a little).

Also one of the reasons I mentioned blade offset is that it was tearing or lifting the edges which often is because the offset isnt right and it lifts the edge instead of cutting and rotating the blade (and sometimes the blade is sticking out to far (often a newbie problem)).

No. If you have some problem or another, addressing it by diddling the offset is merely masking what is really wrong. If nudging the offset mitigates whatever you're attempting to correct, it's only a secondary, or perhaps tertiary, effect. You haven't fixed anything.

The offset is the distance from the tip of the blade to the center of rotation of the blade. Period. On Graphtec style blades it's the radius of the blade. This NEVER changes. No matter how far out of the holder you stick the blade.

If a plotter is leaving ragged, incomplete, and/or lifted corners, the first place any experienced plotter wrangler looks is for contamination on the blade and/or on the tool carriage. More often than not just blowing the dust out of the tool carriage will fix this. Then a dull blade. Then a malfeasant cutting strip or blade holder.

The reason that dust in the carriage is the prime suspect is because it slows the blade up/down movement leaving the blade up when the plotter thinks it's down and, worse, leaving the blade down when the plotter thinks it's up.

Moreover, setting the blade exposure using a credit card [way too thick] or a feeler gauge will expose the very delicate blade tip to needless violence. Most of the time you're only cutting .002' to .003", this is almost impossible to set visually. You should hold the blade holder in your hand, as perpendicular as you can manage, to a piece of scrap vinyl and slowly extend the blade until, using your hand, it cuts the vinyl and just dents the backing.