Can someone please clarify "cutting pressure"?

[airstuff 0]

Just bought US Cutter MH-871. Looking to cut airbrush stencils using mylar. The general consensus seems to be using 100-120 cutting pressure. I cut several stencils out of 7mil mylar at 100 and it was a breeze.

My cutter is rated for "500 g pressure". Logically then, I should be able to cut 10mil and even 14mil mylar with no problem... right? So how then, do you determine whether or not you're using the right amount of pressure? What exactly happens that notifies you that you need to adjust cutter pressure?

Thank you

[kenimes 42]

You are using just the right amount of pressure when the blade cuts through the mylar, but not through the backing. So, if 7mil mylar cuts like butter at 100, it would be safe to assume that 14mil mylar would cut like butter at around 200g of downforce, or thereabouts. You can also adjust the blade depth to set it right for the particular thickness you are cutting.

[airstuff 0]

See... That's where my confusion is. I've read in numerous threads where folks, when they go to thicker material, simply adjust the 'down force'. So, using the above example... going from 7mil @ 100 to 14mil @200... Will the 'force' adjustment be enough? Or do I have to pull the blade out a tiny bit more as well? The material is twice as thick. Others say you have to adjust the blade and leave the pressure like it is and yet others say you have to adjust both.

Actually, at the risk of sounding completely ignorant (which I am in this regard), I will ask the question that no noob seems to want to ask... The basic of all basics in "cutter-world"... What is 'downforce'? (A) Is it the pressure (tightness) that pinch-rollers, which hold the material, press against the machine base in order to hold the material firmly in place? Or... ( Is it how hard the blade/holder push into the material while cutting?

There... I said it. 

[Guest sciondrgn]

See... That's where my confusion is. I've read in numerous threads where folks, when they go to thicker material, simply adjust the 'down force'. So, using the above example... going from 7mil @ 100 to 14mil @200... Will the 'force' adjustment be enough? Or do I have to pull the blade out a tiny bit more as well? The material is twice as thick. Others say you have to adjust the blade and leave the pressure like it is and yet others say you have to adjust both.

Actually, at the risk of sounding completely ignorant (which I am in this regard), I will ask the question that no noob seems to want to ask... The basic of all basics in "cutter-world"... What is 'downforce'? (A) Is it the pressure (tightness) that pinch-rollers, which hold the material, press against the machine base in order to hold the material firmly in place? Or... ( Is it how hard the blade/holder push into the material while cutting?

There... I said it.   

When you talk about down force versus moving the blade in/out you will get all kinds of answers, Its really whatever works for the material you are cutting..  You have to find the sweet spot for your material, Like when cutting oracal 651, My machine's pressure is set to 85 but others will tell you with the same machine they are cutting at much higher pressure. When I go to oracal 751 I have to back the pressure down to about 75, 751 is .5 thinner. So every machine seems to have its sweet spot for cutting..

In your case with cutting myler thats a huge difference in thickness you will want to experiment with the blade depth and pressure to find the sweet spot, if you do have to adjust blade depth because of the amount of difference in the thickness your working with what you may want to do is get another blade holder and have it set so its as easy as just swapping out the holders and upping/lowering your pressure to what your cutting.

[airstuff 0]

OK.. So "playing with it" until you find the spot is the way to go. One last thing.. If I may... the last part of my post above:

What is 'downforce'?

(A) Is it the pressure (tightness) that pinch-rollers, which hold the material, press against the machine base in order to hold the material firmly in place? Or...

( Is it how hard the blade/holder push into the material while cutting?

Thank you so much. I'm getting there

[mars 45]

The downforce of the blade holder is what is meant by cutting pressure. 

If you have 8 mil of blade exposure - you can set blade pressure to cut completely through 7 mil material and 1 mil into the backing.  If you move to 14 mil material you will need more blade exposed to "reach" the backing paper.

The pressure of the pinch roller is adjustable by manupulating the pinch roller assembly.  I've never had to adjust mine.

-Mike

[Guest sciondrgn]

OK.. So "playing with it" until you find the spot is the way to go. One last thing.. If I may... the last part of my post above:

What is 'downforce'?

(A) Is it the pressure (tightness) that pinch-rollers, which hold the material, press against the machine base in order to hold the material firmly in place? Or...

( Is it how hard the blade/holder push into the material while cutting?

Thank you so much. I'm getting there

Your Down force is the amount of pressure put down by the blade/holder onto the material while cutting

[airstuff 0]

Very clear now. Thank you all so much. Now, I must go mess with the 'force'

[kenimes 42]

[Brandon_Davis 1]

Cutting Mylar can be challenging especially because it ruins blades awfully quick! It can eventually lead to cuts that are very rough...

[BannerJohn 1,324]

when I  change Vinyl types, I always do a small test cut...a very small one..and keep doing it til it's right. That is really the only way to be 100% sure.

[BannerJohn 1,324]

Cutting Mylar can be challenging especially because it ruins blades awfully quick! It can eventually lead to cuts that are very rough...

The same is true of Chrome vinyl as well.Anything metallic..and Reflective is a whole 'nother story. It will dull a blade fast.

[airstuff 0]

Cutting Mylar can be challenging especially because it ruins blades awfully quick! It can eventually lead to cuts that are very rough...

Just so I'm prepared then... When you guys say "dull blades awfully quick"... I'm getting ready to cut about 200 stencils on 7mil mylar and each is about 3" x 3". I just got 3 new 60deg blades. About 1/2 the job are fairly simple designs and the other 1/2 are very detailed. I've cut 3 detailed ones and they came out beautifully at 150g pressure. Do you think those 3 are enough to finish the job or should I order more?