UPS for 3D Printing

The three-dimensional printers see a lot of run time here at KautzCraft Studio. The larger prints run for twelve hours or longer. A lot can happen in that time span. Here in Texas and I am sure everywhere else, the weather can change for the worse.

That can lead to power interruptions which can kill a print job in the eleventh hour. It has happened often enough that it became a high priority to find a solution.

Many of the newer three-dimensional printers now offer power interruption protection and can be restarted where they are stopped mid-print and resume the print. That’s not always a perfect solution as the printhead is not parked in a “safe” area above the print and can actually “glue” itself to the print as the heat goes away.

The “pause and resume” works well, but when the power is instantly gone as in a power outage, the pause move (to a safe location) cannot be executed.

The obvious solution is a device called an Uninterruptable Power Supply or UPS. The link will lead to additional information. Often called a battery back-up. Used with any electrical device (like computer equipment) that must continue to operate when normal power is interrupted.

The UPS is a power line (usually 120 volt) battery backup system. A relatively large capacity low voltage rechargeable battery is maintained in a charged condition and is connected to a converter (inverter) that produces 120 volts alternating current.

The converter (inverter) is instantaneously energized and switched to carry the load when the normal power fails as during an electrical storm or other reasons.

A UPS is a perfect solution for saving 3D prints that have a lot of time and material required in their creation.

 There are many sizes, brands an features available when selecting the UPS for this task. The choice was a given for me as the brand is owned by my last employer, Schneider Electric -- owners of the APC brand. We used them exclusively as back-up in our energy management control systems.

The proper sizing is the important decision. The UPS is generally intended as instant replacement of power when the normal source in interrupted. Its action is “instant on” invisible and instantaneous supply of the (usual) 120-volt power. The load never “sees” the power loss. 

The UPS is NOT generally intended a replacement for back-up mechanical power generators. It is the “gap filler” between a power failure and the startup time for a motor-generator or other long-term power supply. 

That reduces the cost and maintenance of needing a high capacity UPS. Batteries are maintenance items and need replacement. But the purchaser is free to choose the capacity and run time they need for the application.

My choice with 3D printing is a UPS run time of not more than one hour. Thirty or as low as fifteen minutes would be adequate. My desire is to ride through the usual one or two second “blink out” that we usually suffer in a weather event. Long term outage is rare and a risk I will accept for a print loss. 

It’s the frustration of those few second outages killing a long print that the UPS is intended to relieve. Starting a print in the morning and hearing thunder in the afternoon is not comfortable and cause anguish. 

We have two printers connected to the UPS shown. Each will draw 250 watts when the print bed is being heated. Normal run wattage is about 50 for one printer and 100 watts for the other (part of the 250 total load). Not sure why the difference. The nozzle heater may be larger on the 2 color printer. Stand-by is 7 to 10 watts (steppers and fans off). Except for start-up the high wattage print beds cycles with about a 10% duty factor. 

Peak load is about 500 watts, but it is not likely the UPS would be used when first warming the print bed. Average run load (per printer) is 50 to 100 watts. 150 watts with both printers running.

I selected a 900 watt APC UPS. The pure sinewave some units feature is not critical. The UPS unit wattage needs to be adequate for the full wattage it is intended to support when it assumes the load. It is also an indicator of how long it will operate under the load. The price class for the UPS shown here is ~$170.00

The Schneider APC has intelligent controls that display the power (wattage) being drawn. It then computes the run time for the present charge of the battery. (Other brands may operate differently) With one printer operating the indication is the UPS can carry the load for one hour on the battery. That more than meets my goals. Two printers would probably run for thirty minutes.

I have produced a video that demonstrates the action of the UPS in a simulated power failure. There is absolutely no hesitation in switching to the UPS when power is interrupted. The same when going back to normal power. 

The UPS fully satisfies my needs and peace of mind about running long prints. I must point out my computers are NOT using the UPS so long prints are always run from files loaded by SD memory. There is no particular reason the computer could not also share the UPS but in my case, the printers are not close to the computers.

I have figured it out! -- Why I am so hung on 3D printing.

I thought it was the actual printing. That is only part of it and was a huge part when I started a couple of years ago. The fascination of the process and how the machines operate is what got me interested. Watching a FDM filament printer running under CNC control was mesmerizing. It’s still that way today, but not like when I first started.

I have owned six different printers and still have five of them today. One of them is a DLP, resin and UV light. My first delta style printer I gave away when I upgraded to a slightly larger Delta of the same make and style. The printers are simply a tool. They create but are not themselves creative.

I realize today that printing is not what keeps me going. Once mastering the machine operation process and understanding several dozen variables and how they interact, printing is quite boring. Load a file, check parameters and material, push start and I am finished for one to twenty hours while the printer does its thing. No fun there.

What I really get excited about is the CAD drawing and the total control of creativity the computer drawing provides. The CAD is also just another tool. The 3D printer gives me the ability (the POWER) to produce a tangible item that I know I can make with the CAD drawing I have created on the computer screen.

It’s not the (brand) name of the CAD program that’s important. Like the 3D printers, some are easier to use or have more features than others. What works for one person may be a problem for someone else. The CAD doesn’t create anything. It is just a tool. It’s all about the person using it and their skills with the tool.

I had to learn the limitations of the printing system and design my creations within those limits. That is the same for any creative or artistic process. It’s that knowledge of the tools that separates the pros from the rookies.

If I couldn’t do the design thinking and the CAD work, I would have lost interest in the whole 3D printing operation. For me there was a period of fun learning to operate the printers (the tool) , but there is no creative outlet in just printing someone else’s CAD designs. Caring for and running the printer(s) is just a job, not an artistic expression. The art is in the design work. The fun for me is creating something original from just a conceptual idea.

The 3D printer is a tool that turns ideas into a tangible reality.

The Dimensional Print Studio has joined the ranks of multi-color three-dimensional printing. This is with the FDM (Fused Deposition Modeling) process using plastic extruded filament. The printer obtained, a GeeeTech A20M (the “M” is for multicolor) printer. 

The A20M uses two filaments and combines the feeds into a single nozzle. This permits blending (sort of) of the two filaments. The colors don’t mix and when fed to the nozzle together, come out the 0.04MM tip side by side in proportion to the feed. Like stripe toothpaste in a tube. 30/70, 50/50, 70/30 it will show in the print.

Much two-color printing is done with a nozzle for each color. No blending is possible. Using a single nozzle, requires a purge area to pump out the old color before printing (100%) with the new color. A “purge pillar” is built up layer by layer alongside the intended print for purging. This pillar is “wasted” and thrown away and is a concern for some stingy printer owners.

Two color printing can take up to twice as long as single color printing. So, two color printing is not popular for many folks. Especially if they have an extreme obsession or phobia about “wasting” material changing colors. 

Waste is a product of all forms of crafting and manufacturing. Does a woodcarver obsess over the 50% waste of material in the form of shavings and chips when carving a figure? Did Michael Angelo obsess over the “wasted marble” when carving David? I think NOT!

Not sorry about the rant above. I’ve just heard about wasting material too many times in 3D printing…

The rewards of having color options are quite enjoyable. For me it has moved my printing further in the realm of an art form, without the need for priming and painting. Or printing multiple pieces to assemble. That will go on, but it is fun to design and see it produced in a single print.

Here are some examples of my first prints. Surely there will be much more to come.

This is my first print in two color. It is my own design created in Fusion 360.	The A20M came with a mouse pad!. The rectangle is the purge piliar required to clear color from the single nozzle.
This is a key fob I printed with different color loaded.	The W5EHS is my amateur (ham) radio call sign
This is a process of blending two colors into a single nozzle printer.	Because the colors don't truely mix, the pink rises higher on the right side and the green is lower on the left.
Quilting square coaster I designed in single color has been updated for 2 color printing.	Same pattern, just switch colors when slicing.
Here is a blended color FDM owl nect to a DLP resin printed owl.	Another blended color print. This time red to grey