Magnetic Material
Hi,
Firstly, haven't used Magnum magnetics, to expensive in Oz, but have tested it, along with a few other brands.
I use several different magnetic materials that I print on with my Roland 640i. They are 0.8mm car magnetic, 0.3mm thin film printable magnetic, adhesive magnetic material for use with iron receptive media.
With all magnetic materials, first is application based on the magnetic force each material offers, given that all printable materials are the same. I do not laminate as a given rule, add to the risk of the overlaminate not matching the printable magnetic material.
I randomly check a section of media after each significant print run on a crude method as follows :
- Using several pieces of standard A4 80gsm photocopy paper, a piece of magnetic material, a vertical metal board.
- I keep adding pieces of paper between metal substrate and magnetic sample (vertically) until the magnetic sample no longer holds and then count the number of sheet/pieces of paper as a measurement.
I have further had some pieces measured in a lab to check the true magnetic force to determine a scale of my crude method.
I have then been able to check rolls of material, if they match up against the manufacturers claims. I finally found one that produced product that was consistent in force.
In regards to the problem above I can only deduct the following :
1. Need to verify the magnetic force is consistent over rolls of products. If it is low/weak, then the probability of edge curl outside becomes greater. Does it match the manufacturers claim for magnetic force grams per cm2. Maybe inches for you guys.
2. Overlaminate can play a roll but not if the magnetic force is strong over 30g/cm2
3. Ink play a significant part in edge curl, just the same as vinyls. I have conducted tests of vinyl cut graphics with full bleed, 100% black on two different printers, one using roland ink, the other cheap chinese ink (about 1/20th of the price of roland eco max 2 eco solvent ink) on the same media. One should curl after a few hours on the edges and continued to get worse, the other didn't over any period of time.
I have found dealing with material suppliers over the years difficult until you can technically show with basic analysis and testing that there is a problem. Often it is the user.
Cheers