Table of Contents
Introduction including Needs Assessment and Problem Formulation5
Methodology6
Background7
Abstraction/Synthesis8
Alternative Solutions9
Design Analysis/Design Matrix12
Final Design Solution13
CAD and Specifications for Exhaust Fan Motors15
Conclusions18
Logbook:19
Table of Figures
Figure 1 12
Figure 2 13
Figure 3 14
Figure 4 14
Introduction including Needs Assessment and Problem Formulation
Temperature control in 3D printing can cause major problems if done incorrectly, throughout this report the team investigates potential problems that cause by a 3D printer overheating or not heating the plastic enough. The most common 3D printer errors are all caused because the part did not solidify fast enough often called stringing or oozing which will ruin the printed piece. Secondly, the part will often not stick to the bed if the temperature controls are too low and it will produce a scribbled mess. Lastly and one of the most common errors with temperature controls is that the plastic can overheat preventing it from solidifying making the fine details of a printed part completely inaccurate.
Overall these types of problems are not often found in all printers, some of them will have fans or set printing times so that air can circulate through and the machine wouldn’t be running for long periods of time. Although these printers are often very expensive or built for commercial use there is the possibility to bring some type of temperature control technology to home printers, and this is also one of the topics that will be addressed in this report. The team will look at various parts of a 3D printer in order to determine which are the major contributors to temperature control and if any of the technology found in commercial 3D printers can be downsized to a home 3D printer. The main topics of research that the team came up with were, the extruder, fans or air circulation and possible air extraction from the 3D printer. Also, 3D printer running times are going to be looked at to possibly determine if some 3D printers especially those used in the Wentworth school library are being overused causing the machine to produce overheated parts. This will also affect the longevity of the actual printer. These temperature control research will be made in order to improve 3D printing standard.
Methodology
Since 3D printing is relatively a new technology, professional engineers and engineering students are always trying to improve such a revolutionary technology. There are many aspects to look at when trying to improve 3D printers in general, for example, energy consumption, support structure, stringing, etc. However, the focus of this report is going to be on 3D printers overheating and or temperature control issues. The main topics of research that the team came up with were, the extruder, fans or air circulation and possible air extraction from the 3D printer.
The methodology that will be used to improve on this issue is to firstly choose the focus of this research from the previously mentioned topics. And then research and gather information in order to define the source of the problem and what causes overheating. Secondly, research previous attempts to solve this problem and learn what to do and not to do. From there the team will use what they learned during their studies at Wentworth institute of technology to develop a solution to the problem. The team will also be consulting with professors who are considered experts when it comes to 3D printing and seeks their guidance and advice.
Background
In today’s society, we can see that there is a vast growth of people 3D printing or wanting to learn this new skill. As mentioned before the Wentworth school library is practicing 3D printing on a day to day basis and developing this skill even further. With the many different brands of 3D printers at our school, we must first understand what is 3D printing and how does it really work. When defining 3D printing we can say that it is a process in which we are making 3 dimensional solid pieces from a digital application we call CAD. The CAD application stands for Computer Aided Design which is where it really begins with what you desire to build. With this additive layer process different materials can be used depending on the machine being used.
We see through history that back in the 1980’s was when people started to mess around with 3D printing technology and back then people used to call it Rapid Prototyping. As time went on, we really see the growth of that technology when a company by the name iMakr opened the first largest 3D printing store in the world for business, it was located in London. This launch was tremendous because we see later on that the market value of 3D printing would be worth $10-billion-dollar. From news, we also see that Google has been making $100 million dollar investments to various 3D printing. Even NASA is trying to create a 3D printer to be used on the moon but the difficulty with that is they have to equate for the moon's gravity when building the machine so the object doesn’t fall apart. 3D printing has exploded in many different areas, industries, and business across the world making our lives easier by just building what we want instead of buying it. In addition, picking up this new skill is something that your average citizen has so it couldn’t be beneficial to have this trait down the road.
Abstraction/Synthesis
3D printer, also known as Cartesian Robot, because it gets that name from its use of Cartesian coordinates when printing. It moves along x, y, and Z axis in order to put down layer on top of layer until it prints the finished product. Some of its component includes, a stepper motor to drive the plastic material into the hot end, the Drive Gear pushing down the plastic into the hot end, the Nozzle which is screwed into the extruder block and the extruder block also called hot ends which are heated to 270C and monitored by a temperature sensor.
The overall mechanical process involves lots of heating. Because of all the heat present in the extruder area in melting the plastic, this heat if not dissipated causes great malfunction. The extruder commonly considered the core of the printer due to all the mechanics that happens there. It is where the plastic is drawn, melted and pushed out.It is basically where most of the printer’s technology is located.
The hot end section of the printer is necessary to have a 3D printer. However, this heat should be restricted to the hot end section to not affect sections that should remain cold. To this end, heatsink and fans are included to ensure that the filament remains solid and rigid above the column section in order to push down into the molten filament below. As mentioned before, this method of cooling does not warranty perfect dissipation of the heat from the heat end. Some common causes mentioned by litterature are dust around the drive gear, broken piece of plastic in the silver column, carbon built on inside walls of the silver column, carbon built in the nozzle.
Alternative Solutions
The current 3D printing market does not offer an effective cooling procedure included in their printers. Temperature controllers are now being sold separately by third parties as an alternative solution to the 3D printing overheating problem. The team has also come up with various ideas that could be physically implemented to the printer or some that involve the printed material. The team’s alternative solutions include, to install a temperature control in which the machine shuts down and turns back up at given temperatures, the next solution would be to install fans next to the extruder, hardening the material faster and cooling the extruder at the same time, third was to test a printer and see how much material it used before it overheated and according to this specify a certain amount of material to which at the end of the printing period the machine would shut down. Finally, the last idea was to implement panels on which the heat was forced down to the printing area instead of the extruder. These the team thinks are all viable solutions to the given problem and are explained much more in-depth in the following pages, after this, the team picked a final solution that would fit best. The final solution may include different parts from different ideas and will be presented in the final solution section of this report.
One of the possible alternative solutions was to install a temperature control system to an existing home-used 3D printer which is now being sold by various companies. The only flaw with these temperature systems is that since they are not connected to the printer itself the controller cannot shut the printer off. This is a critical part of the overheating problem if the printer cannot be shut off then it will keep printing and overheat. So the team’s idea was to install a temperature controller that will read the temperature of the extruder and connect that with the power supply of the printer, so one the extruder hits a certain temperature the controller will cut power to the printer effectively shutting it down. The problem with this solution is the possibility of hurting the printer’s battery by suddenly cutting the power to the printer possibly multiple times during the print. So a more elaborate solution would be to connect the temperature controller box to the printer’s control panel and if possible put the printer on hold until the temperature drops.
Another possible alternative solution would be measuring the amount of material used before overheating could take place. From this we would specify the amount of material so by the end of the printing period we would preset the machine to shut down. This idea replicates how we normally refilling the paper for printer’s same concept but were paying attention to the overheat factor by the amount of material we refill the machine with. The team’s idea with this proposal would watch the amount of material filled into the printer with and thus overheating would actual never occur this way. It would come close to overheating but would never overheat because there would be no material for it to continue whatever you're making. Some of the negatives that come with this solution would be that you would have to keep refilling the machine with the material once it would run out. Another issue that could arise would be that if whatever you're making that needs hours to build could take you more time than expected so the timing to finish things could take longer. It’s important to note that not all the material behaves the same way so by refilling the machine some materials could last longer to refill versus others by the way they behave under heating. Overall we hope but by the results we get that we can make a good estimate of how much we would need to fill the machine with so the extruder would come close to overheating but never reaching it. By the time it would take you to refill the machine this extra time would benefit the machine to cool down for a bit and then continue printing.
Another solution considered the fact that one of the major problems when it comes to 3D printers is not the heat itself, but rather the where is being heated. In such printers, heat is necessary to melt the plastic for a successful process. The heat being generated, is to be controlled to a specific region called “hot end.” That section is considered the molten region as the plastic’s melting starts until it comes out of the nozzle. On top of the Molten area is the heat sink, which its purpose is to dissipate the heat lost in the process. In fact, that heat naturally moves upward and needs to be neutralized in order to not to heat the rest of the system. In many instances, when overworked a lot of heat continuously need to be dissipated causing the top of the silver column to heat if not cooled efficiently by the heat sink. In such cases, a scenario that likely happens is that the plastic starts melting outside of the “Molten Region” which could block orifice and cause other damages. In compensating for the amount of work to be done by the heat sink, it would help having some kind of return fan that could suck some of the heat returning to the top. This heat would instead be push out of the region completely leaving the rest of the work to be done by the heat sink more manageable.
Our third alternative solution to our overheating issue is to install an extra fan next to the extruder. The purpose of this fan is to harden the material faster and cool the extruder at the same time. Cooling becomes important when a user tries to print very small object with a lot details at a quick rate. Which is were a lot of the overheating issues occur. A major concern with installing an extra fan to the extruder is the power supply. Will it be connected to the same power supply as the printer itself? Or Will it be connected to a separate power supply? The team believes it’s best to connect the fan to the same power supply as the printer. This way the fan will work as soon as the printer does, so the user won’t have to manually turn on the fan. There’s a variety of shapes and sizes of fans in the market, but a 92-mm regular computer fan would do thejob.
Design Analysis/Design Matrix
Our main objective is reducing or preventing any overheating from happening in industrial or commercial 3D printers. With the solutions that our team provided we’re hoping that one of the solutions that we end up using will be cost effective as well as time-saving. With 3D printing the item that you wish to create can sometimes take hours to make. By implementing or combining ideas that we have discussed we are altering the way the printing is functioning to get rid of much problems that we normally see with 3D printers. There were 2 ideas that our group thought that would make sense combining them together to ultimately achieve zero problems with the printer overheating. One was the temperature control system which would tell or alert the printer to stop printing no matter the stage that it was printing at. The second was the Vacuum fan system which basically takes out any pre-existing heating that would be located around the sink area of the printer itself. By combining these ideas, we see that the heat developed would be geared towards only designing and creating the piece. The gains we see is that monitoring the temperature helps tremendously because not all material in the 3D printer are the same so the way they adjust or absorb heat can be different. From this, we can see that oozing wouldn’t take place either because our eyes would be on the how hot the 3D printer would get and not allow it to happen. We see that combining ideas helps eliminate problems that would occur if we just implemented one idea rather than both. From this 3D printing overall look will be looked at differently since how much time we're going to save as well as having a strong grip on heating control and how we distribute it efficiently.
Final Design Solution
After considering the different solution and weighing how one would better achieve the purpose of the design, it was determined that the overall solution was not one of the proposed solutions. In fact, with every solution considered some flaws emerged that another design did not have. In final, it was determined that the final solution would be a combination of the solutions. The first section of the design consists of a temperature control system. As the name describe, this system should control the temperature of the printers around the heat sink area in order to determine if the heat sink is able to handle the heat generated. One the temperature sensor detect a temperature higher than what’s normal, a stop signal will be initiated. However, this signal would allow the design in session to finish printing to not cause defects in the way the printed design come out. Also, to make sure the machine does not overheat while the print finishes, the system will trigger a secondary cooling system to help the machine cool down. This system would include an additional fan next to the extruder to reduce some of the heat from the extruder this solution also in general help with the print itself as it helps the plastic solidify quicker. The fan will be small enough to not blow air at high speed which would cause some issues in the precision of where the plastic falls. It will be large enough to be able to compensate for the work that the heat sink is unable to do. In most cases, this solution should work fine in maintaining the heat at a certain level till the print stops. In some cases, it is anticipated that the machine could start overheating in a middle of a long print, in which case the heat might not dissipate fast enough. It could also overwork the fan which at its turn would produce some heat. Lastly, to compensate for any kind of inefficient heat dissipation at that stage, an additional section will be added. This last section would work as an air-source heat pump pulling the warm air into a small tube.