|
| Posted on 4/18/08 at 10:27 AM | |
|
Just a few thoughts that can help people when they are shopping for presses based on speed. I have seen a lot of hurt feelings and general disgruntled-ness out there so I thought I would throw this in. Tony B. is being pretty forthright and careful in his speed estimates. Many people when shopping for an automatic are already contemplating what speed they can get up to in dozens per hour....even before they have ever operated an automatic. I have seen the issue of a year down the line when they have their loading technique down pat..of people grumbling that they thought "X" machine would have eventually been faster when they bought it. You should think about this: Lets see an example job: Say...five colors, one flash with 12" average image area on all screens, wet on wet design for the other four colors. The wild card as Tony notes is your loading ability and consistency at loading. But this is only part of it. There are other issues involved. More stats please: Lets throw in an average flood speed per screen of say 2.0 seconds per print head and a squeegee speed of 2.0 seconds per head. Add an up index of say..1.0 seconds and a down index of 1.0 seconds. Travel/rotation speed from head to head of the ring of say.....1.5 seconds. Each stage in the print now has 7.5 seconds involved with which to complete its print and move on. Flash time will actually be irrelevant to this test job as it will be 3-4 seconds on the second head....well within the 7.5 seconds of print cycle (so yes...buy a good flash) A skilled loader can load a shirt on cycle within say...5.0 seconds. The unloader should match his speed...no problems there. So, within loader speed @ 5 seconds per shirt that is 720 shirts per hour = 60 dozens per hour. Awesome! Hold on now....at 7.5 seconds per print and travel cycle governing your loading and unloading speed on timer...you actually get...40 dozens per hour. When you set up all of your squeegee and flood speeds...which are governed also by off contact,.... which is goverened by screen tension, ink consistancy and coverage area of each print color....you get an overall dwell time for head to head print speed. AND...as Tony noted (i'm betting you were taking some of this into account)...that this is "real world" dry cycle time. not just non printing machine cycle speed. There is no doubt, that with the finer index settings available in the control panel, superb high tensions on screens and great attention to detail, you could set dry cycle times that exceed the 42 doz/hr that was noted...you have to be realistic in the diligence you plan to invest in every other part of the job. Also...five seconds load per shirt is a pretty good loader. You can set squeegee speeds a bit faster and also flood speeds. But that is also a function of ink and tension almost more than just what the machines drives are capable of. Lastly, what many printers do not calculate in the dozens per hour problem, is that if you only have one hour of printing to do on a given job (base on 42 dozen = 504 shirts)....you also have to subtract set-up time loss (better get a pin system)....and any ink adding time (plan ahead with bucket and goop scoop placement or get some ink picarillos)...and how many times a loader in his haste poorly loads a shirt. In the end, its how many GOOD shirts per hour you print. It makes no sense to print 50 dozens per hour when 2 dozen are scrap. True sustained cycle times with good print settings and screens can really only be logged whney ou have sustained print runs that are multi-hour....say a 2500 run. Of course...printing faster at all times makes the short 300 shirt runs that much more profitable too. I think its is safe...to not worry so much about what the machine can do...but what YOU are going to do with it. Just some thoughts and calculations to keep in mind when shopping for an automatic. Ray | ||
 
|
