Introduction
We created this article because we saw a lack of information when laying out electric for our new facility. Energy consumption in 3D printers is seldom talked about, since power draw for a single printer is not terribly significant for a standard hobbyist. However, energy consumption can have a large impact on 3D print farms when volumes for printers are relatively large. 3D print farms are loosely defined as “a collection of 3D printers intended for speedy production” (all3dp.com). With a large number of printers at use, the best printer practices become helpful down the road for their cost and energy-saving potential. Many people do not realize the electrical requirements they are when running multiple machines and may not have the needed power available to safely run their machines. The data below was collected using a CR-10S but should be relatively similar to other comparable desktop machines.
Innosek's Farm
Innosek’s FDM print farm currently consists of 32 FDM printers, with 31 of the printers being modified Creality CR-10S printers, a widely popular FDM desktop 3D printer due to its combination of excellent print quality, build volume, and competitive cost. Our team conducted an energy study on the CR-10S to help further understand how electricity is used by the printer during 2 main stages of printing. The 2 main stages of printing are the time during heat-up, and then when printing ensues with temperatures needing to be held constant.
CR-10 Power Study
The CR-10S has a stock power supply rated with an input voltage of 100-120V and 60 Hz (used here in US), or 200-220V and 50 Hz in other respective countries where necessary. The output voltage is rated for 12V and 30A. Note that this study will only be including information for this configuration, and not other printers/countries where electrical configurations may differ. This power study was done with single phase 120V power in the United States. Please use this information at your own discretion.
A standard PLA (polylactic acid) print requires a hot end temperature around 200C and a bed temperature around 60C. During the heat-up process and the beginning of the print, values for current (A), and power (Watts) are recorded to see how they change over time. The following graph displays current over a period of 6 minutes.
At around 315 seconds, the print heat-up completes, and the current begins to oscillate. This is because the hot end and bed need to only maintain their current temperature, and are no longer “heating up”. The print bed draws the most current. The spikes in the oscillation is due to the heater cartridge and bed heater now only needing to maintain temperature. Therefore, quickly switching the current to a min/max value can produce an average power required to maintain the appropriate temperature values. When determining electrical requirements, the peak power should be used.
The following graph displays current and power on the same plot over a period of 6 minutes.
From the graph above you can see the direct relationship between power and current. With the equation [ Power = Voltage * Current ], we can see voltage remains constant for the most part. From this data, a rough estimate can be made for the energy consumption over a print. Using numerical integration, the heat-up time standalone consumes 0.0268 kWh. This transfers over to $0.0048 for each printer to heat up for a PLA print.
For a print after heat-up, the power consumed obviously can vary since print times can be anywhere from 5 minutes to several days. A fair estimate for the average print time at Innosek is roughly 8 hours. During this the current oscillates from recorded values of roughly 0.8A to 3.8A (corresponding approx. 55 W to 280 W). During this study, the power factor, PF, was read from a range of 0.55-0.65, based off what the instantaneous current/power draw was. The following graph was a sample taken of power values for 2 minutes of a PLA print (note these readings are taken in 1 second intervals).
From these values, an average value of 130.09 W is measured. For an 8-hour print, we can estimate this will consume 1.041 kWh.
Assume each printer does two 8-hour prints daily, which will consume in total 2.081 kWh ($0.3740 daily, based off avg. We are located in New York State, where in 2019, The average electricity cost was $0.1797/kWh). In total, 32 CR-10S printers running two 8-hour prints for a year daily would cost roughly $4,400. This means each CR-10S will consume roughly $136 of electricity per year if only PLA temperature configurations are used. Note that this calculation also does not include standby time (standby time is when the printer is on, but none of the heaters are on nor motors).
It should be noted this value for the electricity bill for 3D printers standalone can vary by reasonable amounts, since prints can be started with different temperature requirements for the hot end and bed. For example, a study for bed heat-up time was conducted using the stock CR-10S bed vs. an upgraded silicone heated bed with a SSR (solid-state relay). The following graph shows heat-up times for each respective bed to a variety of temperatures.
For a PETG build on a printer with an upgraded bed (750W bed, 255 Nozzle, 90 bed) the following power vs. time data is plotted.
Amazingly, this heat-up process consumes 0.026952 kWh, which is almost identical to the energy consumed by a stock CR-10S for PLA heat-up (200 nozzle, 60 bed). Even though the bed and heater can draw over 800 W when simultaneously heating, this large power draw is offset by the relatively short duration it is needed compared to a stock heated bed. Please interpret the data and findings in your own way, electricity is dangerous and we are not liable for any issues that may arise.
To conclude, power draw from printers can truly be a valuable study to look into when printer volumes become substantial. Print farms should look into best printer practices to save energy/money, as well as maintain printers and their respective power supplies. To determine optimal electrical/fuse configurations for a set of printers, an energy study like this one may be necessary to safely operate many printers at once. You can get an inexpensive meter to record voltage, wattage and current online.
Power Requirements
At our old facility, we were constantly tripping circuit breakers because we did not understand how many printers could be running on one circuit at a time. It is not a fun time when you trip a circuit breaker that is powering 8 3D Printers at once and possibly losing all 8 prints. When moving to the new facility we wanted to make sure we had enough power at each outlet. We decided to create a rule that all 3D printers have a dedicated plug, no 6-way outlets or splitters allowed. If the printer is connected directly into the outlet, it ensures you have enough power to safely run the machine. During the power study, we found a peak amperage of about 4 amps. On a 20A circuit, we can safely run 4 printers at a peak of 16 amps, which is the recommended max amperage on a 20A breaker.
Most circuits in homes are rated for 15 amps, which means that you should not exceed more that 3 printers per circuit breaker (assuming you are not powering anything else on this circuit). Changing the breaker from 15 amps to 20 amps is most likely not an option since the wire used on the 15 amp circuit may not be rated for 20 amps, causing a potential fire hazard. Breakers are designed to fail before wires get hot and fail. You may need to consult with an electrician to make sure you have the correct power needed for your setup and to possibly install dedicated power. Your electrician should be able to determine how much current is being used on a circuit. Better safe than sorry.
In summation, you should dedicate at LEAST 5 amps for your desktop 3D printer, possibly more depending on your machine and upgrades. Keep on 3D printing !
Credits go to Ryan Cavallaro on the Innosek team for performing this power study. We hope this information is helpful to you. Ryan is a recent Mechanical and Aerospace Engineering graduate from the University at Buffalo who has been an integral part of the Innosek team since 2018.
Tags: 3D Printer Amperage, 3D Printer Power Requirements, 3D Printer Electrical Requirements, Additive Manufacturing
We are not responsible for any issues that resolve from information in this article. This information was created for public knowledge and awareness.