I have just read all the thread and totally agree with lyratron and TypeR, and the guys in the end talking about considering the time required to print an order with FDM printers. (I am sorry guys, this will be a long comment.)
For 3DHubs, up to now, I have considered start-up price to be equivalent to 1 hour printing and the $/ cm3 to be $ / 1 gram weight of material to be used. This is to say I neglected the cm3 dimension and replace it with gram. I need not to know the density of the material. All I know is how much does it costs me per Kg or g. Suppliers do not provide density information.
In the end of September I commented on this issue to the support person asigned to me:
"…1. 3D Hubs quotes on a startup price per job. On the other hand, I cannot charge per job since I estimate a price per hour-machine (this is the number of minutes the printer will take to print the order) plus material used for the printout plus delivery conditions.
I am considering the startup price to be equivalent to one hour printing, then I add up to the price the fee related to the extra-time needed to finish the print. This is the startup fee times the number of hours (or minutes) required to print the object.
"…4. Also in 3D Hubs base quotaton, volumen of the object is considered. But, softwares like Cura, provide an accurate amount in grams of the material to be used. "
(If not accurate at least it gives a very good approximation. I have compared several times by weighing the printout.)
Popular slicers like Cura provide estimated information on time and amount of material to be used, this allows to easily estimate a price. I think estimating the price per job is very inconvenient since it does not consider the time required to complete the job. And, on the other hand, estimating the material cost per volume may give a good aproximation when you do not have slicer sofware at hand or when you are on the street and people ask you for a price. But if you have slicers that provide time and weight info, then why not to take adavantage of that?
In my opinion, Hubs (or Hubbers ?) should be free to fill out a simple form depending on the type of printer they use FDM, SLS, etc. In the CNC industry they charge for the time required to machine a piece. It should be the same with 3D printing. No need also for different quote for high quality printings since high quality printing always take much more (?) time to print. As a result, a high quality printing will be always more expensive. The same as with large printings.
About considering weight or volume for material cost, I think both options should be considered in the form. Not just volume. It will be hubber’s(?) decision to choose the method that better suits him/her.
Additional costs is another issue to talk about.
Make it simple.
