OK, First I own a manufacturing company, and consider us to be a teaching company. Our adverting department made vinyl products (adverts / signs) for over 35 years, and we had only Roland equipment. I recently had to purchase a cutting machine for small in house application and did not want to spend the money as I had done in my former business. Let's face it, these machines are built pretty well for the money, but they are not going to produce the ease of use such as $2500 Roland is know for.
I too got a bit frustrated with the blade-cutting issues, too shallow, too deep, and battle because I was used to a machine that performed this action by itself.
Here's the deal. There is a fine point from right to wrong when making the blade adjustments. It is true that the blade needs to protrude very little, and though I did this or thought I did between adjustments I found that I was making too aggressive adjustments thinking what's one or two turns on the blade carrier. Well, I found that is to much. Adjust the blade so it is about the depth of a standard business card (.020 "). I set the machine at 60 grams and worked down each test, and in my case ( using this companies vinyl material ) I good good results at 20 grams.
Of course other manufacturers materials whether cast or calendar grade will require lesser or more pressure. In our case we are using the "outdoor calendar" material.
I would also recommend using the best cutting blades, ( I like 45 degree ). I am however using their cheaper one's which could be why I had such a "fine tuning" experience?
Don't get frustrated they do work well, especially for the money, just make very minimal adjustments on the blade holder, and be sure you do place it back in a bottom out on the cutter head.
While I'm at it a little trick for weeding. Always start at the top right corner and weed to the left or lower left. It's best to have someone walk the paper downward and you pull the vinyl away and off at a upper angle.
Good luck, I hope this helps. Tony C. Warehouse Hobbies Inc. DBA: Rock'in Radios
P.S.- I am quite pleased with this machine (US Cutter MH721) so far?
