dinki

Problems with weeding UNLESS using two pass cuts HELP!

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Hey guys.  Been cutting decals for over fifteen years with a Seiki SK720H and Oracal 651 vinyl.  I cut a lot of decals with small text and up until recently have had problems with dots over the 'i', dashes, slashes sometimes to often staying on the weeded material.  This caused significant frustration and time to recut and manually move. 

 

I had been using Flexisign starter for most of this time but recently switched over to Vinylmaster Cut.  I went through the whole calibration procedures to get everything zeroed in.  All seemed well but I continued to have the issues.  I decided to give two pass cutting a try and now I'm having a much better success rate (~98%) on these small pieces staying on the backer.  I can't, for the life of me, figure out why this is happening. 

 

I've tried increasing the downforce from 120g (leaves slight impression on backer paper) incrementally up to 160g (nearly goes through backer paper) with single pass.  This did not affect the small pieces staying where they should at all.  I am using a quality Clean Cut 45d blade which I purchased a month ago.  I have been using those blades for years.  I've also reduced the speed to see if that helped, but that didn't help either.

Can anyone suggest something to try so that I can use one pass instead of two.  While the two pass is great in reducing my frustrations, it does take twice as long to cut the decals and is not ideal.  Thanks for your time!

 

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The fact that you are almost going thru the wax paper backing at higher force, is too much blade exposed.  It is not possible if the blade depth is set correctly

Oracal 651 should never have to use 2 passes.  It is only 2.5 mil thick. With that Clean Cut blade you may also have broken the tip off, very easy to do. It takes much less force than regular blades. This is the correct way to set the blade depth. 

To start with, you should set your blade depth correctly, by taking the blade holder out of the machine, and firmly cut across a piece of scrap vinyl, you will be cutting. You should only be cutting the vinyl and barely a mark on wax paper backing, Adjust blade to get there, Then put the blade holder back in machine, and use the force of the machine to get there, same results, only cutting the vinyl and barely a mark in wax paper backing. You should barely see and feel the blade out of the blade holder. Regular sign vinyl is only 2-3 mil thick. You only cut with the very tip of the blade. 
 
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I wondered about the tip of your blade as well. Each cutter runs at different downforce numbers but your at 120g which with a Clean Cut blade should be well into your cutting strip. 

I am unfamiliar with the Seiki 720H, is it a servo or stepper motor? If you have had it for 15 years it may be reaching the end of it's life cycle. These things do wear out eventually. 

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Thanks guys.  Should I be able to see the break if the tip is broken?

 

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   Yes, use a magnifying glass, but possible without it.  You are supposed to back your force back 1/2 before you use it. They are extra sharp. The tip will snap right off. 

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this is magnified 60x on one I broke - it happened only once because I make sure to start with too little blade - this one got dropped.  the cleancut blades are made with a finer grained carbide which is why they last longer but the trade off is they are a little more brittle.  I think in 8 years of using them this is the only one I broke.  I personally couldn't tell it without the microscope attachment on my phone 

 

34708778_10204823149655084_5425396520734162944_n.jpg

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Thanks for this.  I just took a close look using a magnifying glass and it appears that the blade is not damaged.  When testing at different strengths at no point did the blade go all the way through the backing paper.  Understood about less pressure needed.  I've used these blades for many years.  In fact, I switched to some cheap Roland 45d knockoffs before switching back to the more expensive Sure Cut blade I'm using now.

 

I think my problem is with the blade depth adjustment.  I'm not exactly sure how to do as instructed though.  The manual process of adjusting and cutting the vinyl by hand is a bit confusing.  How much/little pressure do I use?  Is there something I can use to gauge the blade visually?

 

Thanks again for the tips.  It is most appreciated.

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Put it like this, you shouldn't even barely see the tip out of the blade holder. Or feel the tip out of the blade holder. You only cut with the very tip of the blade. Your vinyl is only 2.5 mil which is hardly anything. Run the blade holder over the vinyl  manually in your hand. If it goes into the wax paper backing , you have too much blade exposed out of the blade holder. If the blade depth is correct, it is not possible to cut into the wax paper backing.   You just want a slight mark on the wax paper backing, that way you know you are all the way thru the adhesive.   There is nothing to gauge, You shouldn't even barely see the tip out of the blade holder.  When the tip is in so far in the blade holder that you think it wouldn't even cut, it is probably right. You use the force of the machine to cut. 

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So here's what I found:

My blade appears to be WAY too far out when comparing to what @MZ SKEETER suggested.  I backed the blade way back and was surprised that, yes, it still cuts even when only that tiny bit is exposed.  I tried by hand and was able to cut out a square that could be weeded.  I moved to the cutter and slowly worked my way from 120g up up up until I was able to cut the cutter's test pattern triangle.  I think started cutting small text and slowly crept up until I was able to cut small text repeatable and all pieces stayed on the backer.  This turns out to be 350g which is way more pressure than I've ever used.  I then started cutting text smaller and smaller.  I cut text from 0.4" to 0.25" with only the 0.25" having any problems.  On that cut, I ended up losing a '1' character.  I think I will try these settings for today's orders and see how it pans out.

 

Again, thanks to all for the help.  You've increased my speed by 100%!  :)

 

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22 minutes ago, dinki said:

So here's what I found:

My blade appears to be WAY too far out when comparing to what @MZ SKEETER suggested.  I backed the blade way back and was surprised that, yes, it still cuts even when only that tiny bit is exposed.  I tried by hand and was able to cut out a square that could be weeded.  I moved to the cutter and slowly worked my way from 120g up up up until I was able to cut the cutter's test pattern triangle.  I think started cutting small text and slowly crept up until I was able to cut small text repeatable and all pieces stayed on the backer.  This turns out to be 350g which is way more pressure than I've ever used.  I then started cutting text smaller and smaller.  I cut text from 0.4" to 0.25" with only the 0.25" having any problems.  On that cut, I ended up losing a '1' character.  I think I will try these settings for today's orders and see how it pans out.

 

Again, thanks to all for the help.  You've increased my speed by 100%!  :)

 

One trick I was told from my SummaCut tech support is to get down at eye level when the cutter is running and be sure you can see a very slight air gap between the blade holder and the actual vinyl. If the blade holder is dragging on the vinyl when cutting you would need a slight adjustment but if it's got some gap and you are cutting through then you are set correctly.

I still question the blade tip. That is a LOT of pressure. Could be that your machine doesn't read accurate gr of pressure but if the very tip has broken or been rounded off it will do similar. I have found that a few times when cutting HTV which is a bit more demanding on blades. If the tip was not pristine I start having issues with needing more pressure and I usually save those blades for use when I need to cut something nasty like glitter. Still useable but not pristine. 

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I agree, I was concerned with having to apply that much pressure.  I do have those cheap blades that I can try.  I'll see if they need the same pressure as the SC blade.  I'm guessing if it's less then maybe the blade is damaged indeed.

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So I gave the new blade a try in another blade holder.  Set up the same as above (little blade showing).  Was able to cut at 150g but had to keep inching up.  Got to 220g and decided to stop.  Still losing pieces while weeding.  Just for fun I went back down to 150g, increased speed to max, and did a two pass.  Weeded perfectly.   I don't know what to think.  Perhaps overcut?  I'm using a value of '1.00' in Vinyl Master.  Admittedly, I'm not sure what that value should be.

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Have you ever looked at your teflon cutting strip to make sure it is free of scratches and gouges?   That could cause many problems.   If your test cut cuts at 150, then you shouldn't have to change it.   Why did you switch off of Flexistarter?   I still use Flexistarter for all of my cutting.  I have since 2006.  If it was working well, why change it?  If you are cutting very small detailed work, you cut on a slow speed.  NOT max.  Never should you ever have to cut 2.5 mil in 2 passes.

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Things you can try and/or inspect:

  • Try changing the blade out again, maybe you have some kind of defect with the blade.
  • Try using a 60* blade. If you're cutting really small text, a 60* will probably do better for you.
  • Try slowing down the speed of your cuts.
  • Check the cutting strip, perhaps it needs replacement. Mine require replacement every one in a while.
  • Check the blade carriage. Make sure that nothing on the carriage is cracked, and is able to hold on to the blade holder securely. I have found hairline cracks in the carriage that would allow movements and cause issues in the cuts.

You'll just have to go back to basics and start ruling things out one at a time.

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