The per hour rate can be applied to all types of technologies but there are different factors that affect how this rate is used for each option.
It is recommended to calculate a price per hour for the machine in question which allows you to write off the machine before it becomes obsolete (2-5 years).
DigiFabster calculates the time it takes to make your part based on either the size of the part and/or it's bounding box and a combination of the following.
SLA
SLA
Nominal growth rate
This is the speed the machine can print in the Z-Axis using your default layer thickness. This could be taken from the machine specs or calculated over a period of time using data from previous prints. In order to calculate this use the following formula.
Average print height mm / Average print time (hours)
Example 200/4 = 50 mm per hour in Z-Axis
Layer thickness
This is used if your customer selects a different layer thickness from your standard default option. For example, if you default layer thickness is 200 but your customer chooses a thickness of 100 microns, the print time will be roughly twice as long.
Example Calculation
Part Height = 230mm
Nominal Growth Rate = 50mm per hour
Cost per hour $10
Layer thickness = 200 microns
230/50 = 4.6 hours
Total cost = $46
SLM
SLM
Nominal growth rate
This is the speed the machine can print in the Z-Axis using your default layer thickness. This could be taken from the machine specs or calculated over a period of time using data from previous prints. In order to calculate this use the following formula.
Average print height mm / Average print time (hours)
Example 200/4 = 50 mm per hour in Z-Axis
Layer thickness
This is used if your customer selects a different layer thickness from your standard default option. For example, if you default layer thickness is 200 microns but your customer chooses a thickness of 100 microns, the print time will be roughly twice as long.
Example Calculation
Part Height = 230mm
Nominal Growth Rate = 50mm per hour
Cost per hour $10
Layer thickness = 200 microns
230/50 = 4.6 hours
Total cost = $46Melting rate
This is the amount of material the machine can melt in cm3 per hour. You can take this number from the manufacturer specs or use data from previous prints. To calculate this use the following formula.
Average volume of melted material (cm3) / Average print time (hours)
Example 12,000/14 = 857 cm3 per hour
If using the Melting Rate and the Nominal Growth rate, the calculation that results in the longest time will be used in the cost calculation.
Example Calculation
Part Volume = 3000cm3
Nominal Melting Rate = 857cm3 per hour
Cost per hour - $10
3000/857 = 3.5 hours
Total Cost = $35If using the Melting Rate and Nominal Growth rate, the calculation that results in the longest time will be used in the cost calculation.
MJF & SLS
MJF & SLS
Nominal growth rate
This is the speed the machine can print in the Z-Axis using your default layer thickness. This could be taken from the machine specs or calculated over a period of time using data from previous prints. In order to calculate this use the following formula.
Average print height mm / Average print time (hours)
Example 200/4 = 50 mm per hour in Z-Axis
Layer thickness
This is used if your customer selects a different layer thickness from your standard default option. For example, if you default layer thickness is 200 microns but your customer chooses a thickness of 100 microns, the print time will be roughly twice as long.
Example Calculation
Part Height = 230mm
Nominal Growth Rate = 50mm per hour
Cost per hour $10
Layer thickness = 200 microns
230/50 = 4.6 hours
Total cost = $46
Fusing rate
This is the amount of material the machine can fuse in cm3 per hour. You can take this number from the manufacturer specs or use data from previous prints. To calculate this use the following formula.
Average volume of melted material (cm3) / Average print time (hours)
Example 12,000/14 = 857 cm3 per hour
Example Calculation
Part Volume = 3000cm3
Nominal Melting Rate = 857cm3 per hour
Cost per hour - $10
3000/857 = 3.5 hours
Total Cost = $35If using the Fusing Rate and Nominal Growth rate, the calculation that results in the longest time will be used in the cost calculation
FDM
FDM
Nominal growth rate
This is the speed the machine can print in the Z-Axis using your default layer thickness. This could be taken from the machine specs or calculated over a period of time using data from previous prints. In order to calculate this use the following formula.
Average print height mm / Average print time (hours)
Example 200/4 = 50 mm per hour in Z-Axis
Layer thickness
This is used if your customer selects a different layer thickness from your standard default option. For example, if you default layer thickness is 200 microns but your customer chooses a thickness of 100 microns, the print time will be roughly twice as long.
Example Calculation
Part Height = 230mm
Nominal Growth Rate = 50mm per hour
Cost per hour $10
Layer thickness = 200 microns
230/50 = 4.6 hours
Total cost = $46
Horizontal Print Speed
This is the default speed at which you print each layer. For example, a single layer has 2000mm of extruded filament and the printer is set to print that layer at 100mm/s. It would take roughly 20 seconds to print.
Example Calculation
Horizontal Print speed = 100mm/s
Total horizontal printing length= 864,000mm
Print Time = 2.4 hours
Cost per hour $10
864000/100 = 8640 seconds = 2.4 hours
Total Cost $24If using both the horizontal printing speed and the nominal growth rate. The calculation that results in the longest time will be used in the final cost calculation.
3-Axis, Multi Axis & Turning
3-Axis, Multi Axis & Turning
Roughing Speed
Roughing speed is the speed at which you can remove the majority of material from the block and approximately shape the part before finishing the part at a slower, more controlled speed. This figure should be based on a material with 100% machineability. This figure varies by machine so you can use either the standard specs from the manufacturer. The general speed your machinists use for roughing or calculate the average of a number of parts.
Example Calculation
Bounding Box Volume = 1000cm3
Part Volume = 300cm3
Roughing Speed = 500cm3 per hour
Price per hour = $50
1000-300 = 700cm3
700/500 = 1.4 hours
Total Cost = $70Finishing Speed
Finishing speed is the speed at which you run your machine during the more refined, slower process of finishing the part. This figure should be based on a material with 100% machineability. This figure varies by machine so you can use either the standard specs from the manufacturer. The general speed your machinists use for roughing or calculate the average of a number of parts.
Example Calculation
Surface Area of part = 580cm2
Finishing Speed = 200cm2 per hour
Price per hour = $50
580/200 = 2.9 hours
Total Cost - $145
Cutting
Cutting
Feed rate (material settings)
This is the speed at which your machine can cut through the thickness of material. For example. A sheet with a thickness of 10mm may have a feed rate of 1400cm per hour but a thicker material with a thickness of 15mm may have a slower feed rate around 1000cm per hour.
This can vary by machine and technology and is just an example.
Example Calculation
Part perimeter = 1300cm
Feed Rate = 400cm per hour
Price per hour = $10
1300/150 = 3.25 hours
Total Cost = $32.50
You can use any and all of the other pricing parameters in combination with this one, the results of each type of calculation will simply be added to the sum total of the model production costs.