HHG - I understand that dies can't be calibrated, what I meant was to check them for wear. IE you set the dial for a 20mm crimp and get a 25mm crimp. I'm guessing that would be a worn die. Emphasis on guess. From there you could adjust the dial or get a new die?
A crimp that is out by 5mm is more like someone put the wrong die in the crimper. Our own crimpers that we sell at DHH have an effective range of 3to 4 mm per die, so it would be nearly impossible to miss by 5 mm. What happens more often is that your crimp is off by one or two hundredths of an inch.
That said, if you don't get what you expected, the first thing to do is to check that you put the right die in the machine, that the pressure plate, die and compression cone are seated properly, and that you set the micrometer correctly. When you're doing that, you also make sure everything is
generously lubricated. 99% of the time, you've just fixed the problem.
On the rare occasion that doesn't fix the problem, you recalibrate the machine. As I said before, this is a relatively simple process on most machines and should only take the operator a few minutes to adjust the calibration.
If you've done everything above, and you are still not getting the proper crimp diameter, then either the die is worn or the crimper is damaged somehow. At this point, I would inspect the die for wear and probably determine it needed to be replaced. If the die isn't the problem after you've gone through all of this, then you have a serious problem with your machine and you should contact the factory for service or help troubleshooting the problem with your machine.
Hose crimpers come in variety of sizes and capabilities. Some of them are very simple mechanical devices and some of them are very complicated with computerized controls. They range in price from about $1k to over $20K. The inexpensive ones usually require less maintenance, but they don't do as much. If you've got a $10K or $20K crimper, then it's probably got a lot of sophisticated electronics on it, and the electronics are hardest things to troubleshoot. We have a couple of these in our shop, and guess what? They're the ones that most often need service. Still, for the volume that we do, and wide range of hose assembly tasks we perform (including hoses up to 2" ID and larger), we need these machines because they do things that our smaller and less expensive machines can't.