Sharp Inner Corner Cuts Not Completing - FC7000MK2-130

[Reaction GFX]

So I've got an older FC7000MK2-130...thing is a workhorse for the most part, but on and off I've had difficulty with sharp inner corner cuts not completing. It's usually only an issue on inner corners less than 45 degrees. Sometimes it'll look like it's cut, but it's just not cut deep enough, other times it fully skips 1/16"-1/8" of the cut line into the corner. I've never been able to come up with a definitive answer why it does this. I've tried changing settings slightly, cleaning blades, new blades...nothing seems to completely alleviate the issue. Again, it doesn't do this all the time, but it does it a lot of the time. I've got 72 24" logos with tons of these inner corners to cut and following along with an X-acto to complete the corners as I weed is getting old.

If anyone has ANY input as to what might be the cause of this and what I can do to avoid it, I'd sure appreciate it.

 

[woolly]

cutting air escape vinyls can be more troublesome. as the vinyl is not held as well to the backing paper, if its the knife thats picking up the corners i wood guess that the blade holder is not free enough and or too much blade showing, does it do the same to standard cut vinyls

 

[Reaction GFX]

cutting air escape vinyls can be more troublesome. as the vinyl is not held as well to the backing paper, if its the knife thats picking up the corners i wood guess that the blade holder is not free enough and or too much blade showing, does it do the same to standard cut vinyls

Yeah, the type of vinyl doesn't seem to make much difference. The only vinyl this doesn't seem to be an issue with is reflective, but I use a special blade and obviously very different settings for reflective. Probably 80% of the vinyl I cut is Gerber 220/3M High Performance, and the unfinished corner cuts is a problem on that vinyl as well. I've lubed the blade holder, and I always do test cuts before every job to make sure the blade is set just deep enough to get through the vinyl without cutting into the liner. I've had this plotter for some time...bought it new in 2007, I think, and I've never replaced the cutting strip. I thought maybe that might be the issue, but I never do any perf/die cutting (through the liner), so as far as I can tell, the cutting strip is still in great shape. Stumped.

 

[Jburns]

Did you try turning on Overcut - like say .010 or so

 

[bannertime]

Try setting the Tangential Emulation to Mode 1 or 2. Mode 1 does an overcut every corner and mode 2 only does an overcut on the start/end. You'd have to set it for each cutting condition. So I'd setup a new condition just like your standard one but have it set to TE M1 or M2. According to Graphtec, this is supposed to prevent the corner errors. I have not tried it, but it's my next step when I run into that issue. I don't generally do detailed cuts on air egress so not something that happens often for me.

 

[woolly]

i have the same plotter and a mk2 as well, this is what i would do, notice in the pics that the vinyl has risen from the edges where its been cut along all the edges perhaps indicating you need a finer blade. the reflective blade you use is probable a 60 deg one so try that obviously with appropriate settings. also as a check against the other blade holder sticking a bit.
clean and polish the bed so the vinyl slips over the cutting strip easier when under the pressure of the blade use all the pinch rollers try again possibly slowing the speed down a bit, possibly add a little to the blade offset. to help the blade swivel around the acute corners

i have read some of the specification of that vinyl it would not be my choice for general use but your in the states and me in the uk so you will have your reasons why.

 

[MikePro]

blade is turning while changing direction, but hasn't turned completely as it starts traveling up the line and skips/drags in the process and doesn't complete the cut. I "dealt" with it for years, weeding vinyl towards the inner corners and completing the cut by-hand with an xacto....

that is, until I started fixing it prior to output:
I filet my sharp inner corners .01", outer corners too. helps the blade make the turn & change direction clean while plotting. ...and its such a minimal radius that, at a glance, its still a sharp corner.

 

[bannertime]

So I've started testing the Tangential Emulation modes on my two cutters. One for regular cut vinyl and the other for my print/lam stuff. It actually improved the corners. I did a small van job last week. On the first van graphics I didn't use any TE mode and while it did okay, the next set I used TE Mode 1 saved me a few minutes in weed time and produced cleaner corners. Highly recommend. We have a new condition setup for lam/cut letters now.

The Tangential Emulation lifts the blade up on the corner cuts and drops it back down so it's not trying to drag over the vinyl. Now it's not true tangential, but TE Mode 1 does an overcut that sets the blade down outside the cut and makes a clean corner. Not the best mode for every job, but it is useful for letters. Mode 2 does an overcut at the start/end point but still appears to lift on the corners. If you've got everything else dialed in like blade depth, right blade angle, calibration, speed, etc then try this.

 

[Reaction GFX]

Some great tips here, everyone! However, I have to come clean...I made a mistake that I'm almost embarrassed to admit. A few months back my 10+ year old, all plastic blue blade holder broke. The threads on the bottom broke and there wasn't enough thread left to securely hold the tip on. Not wanting to spend $105 on an OEM replacement, I bought a cheap, all-aluminum (should be more durable, right??) blade holder off Amazon for $15. It sucked. Never could get it to cut well. Knowing full well that they are different, just for the heck of it I put the tip from the blue blade holder onto the red blade holder with a 45 degree blade to see what would happen and to my surprise, it actually cut okay. Been running like that for a few months and the only real issue was the incomplete corner cuts. This recent larger job that motivated me to make this post just had way too many sharp corners/incomplete cuts, so I finally did the right thing the other day and dropped the cash on a replacement Graphtec blue blade holder. Wow. I'm still getting the very occasional incomplete corner, but overall, I think it's cutting better than it has in years. Looks like they've improved the design of the holder over the years, so hopefully this one outlasts the plotter itself. (Last time this thing needed any service, which was the only time, the main board fried about four years ago. We had a very difficult time finding anyone to work on it. Parts were basically non-existent, even four years ago. I do realize if this thing craps out it's basically a boat anchor and I'll need to buy a new plotter. Trying to keep this thing alive as long as possible!)

Thanks again for all the input and tips. It's all been filed in my brain bank.