Calibration process

[Vtrailway]

New to 3D printing. Recently purchased a Saturn Elegoo 4k printer. I've done some test prints with standard Elegoo grey photopolymer reside that came out well at 2.5 seconds exposure. I printed the cones of calibration using the same settings. The cones failed. I increased the timing of the exposure from 2.5 to 3.7 seconds. The cones printed successfully. The exposure time seems long to me as most information I've seen hangs around 2.5 seconds. Being I'm a noobie, there are other settings I don't understand or even no about. 

I'm printing items to be used in an N scale model railroad. So far I've found a few files on thingaverse. I've printed some girder bridges. The bridge details are spot on and incredibly straight but some edge upward curl from the build plate. 

I'm sure there are tons of variables and questions that need to be answered for assistance with my issue.

[Dan-Gtr]

I've experienced the same discrepancy between Chitubox's default exposure times and "The Cones of Calibration" with my Saturn printers. However, on my printer the "Cones" required a longer Exposure time than Chitubox's default setting. A representative from Elegoo did tell me that each printer could have slightly different light intensities and it might be necessary to use a longer exposure time on one machine when compared to another (I own multiple printers and was expecting them to all use the same settings - which they don't).

Any time I have a print that uses a lot of the Build Plate's area or is tall we need to use a longer exposure time. Our Bottom Exposures are typically around 10-15 times the Normal Exposure time. Long Bottom Exposures could cause a small ridge to develop around the bottom of the prints where theyy touch the Build Plate. Also, the resin will have an influence on Exposure times. My Saturn S printers average somewhere between 2.5 seconds when printing 28mm figures to 3.5+ seconds for a terrain piece in that same scale. An Exposure time of 3.7 seconds doesn't seem too out of line if your piece was heavy or thick.

Resin type and color does have an effect on the exposure time - whenever I print using black or dark gray resins those exposure times have to be longer than the time for a light gray or white resin of the same type.

Hope this helps