Customer Handoff & Final Project Documentation
Team Vision for Final Demo and Handoff
The main goal of the team was to complete the construction of the machine and fine-tune the different factors in order to optimize the production of the extruded filament.
The final product was able to extrude filament at a fairly consistent rate. Once the machine was working, we worked on fixing the electronics panel.
As mentioned previously, the machine does not work perfectly. It is periodically inconsistent in both the filaments properties and extrusion rate without changing any settings. Also, the rollers are an imperfect solution to the cooling and sizing problem.
Looking to the future, to solve these problems, the project should either continue as a senior design project, a grad student project, or a construct project. The work completed by our team is sound, and the problems the extruder faces are not unsolvable. If senior design is chosen, at least one plastics specialist should either be a team member or assistant guide. Finding a better mixture for extrusion, including regrind, would be their primary task. As for mechanical improvements, climate controlling the extrusion, for humidity and temperature should be assessed as well as changing the orientation from vertical to horizontal. Water baths should be explored as a better alternative to rollers. If the rollers must remain, see earlier iterations of the design for better, metal rollers that can both pull and form the extrusion.
Risk and Problem Tracking
- Our Risk Analysis Matrix is shown below for ease of access, it has not changed since the last update.
- Almost all risks have been successfully avoided, and those that were not avoided were mitigated by having plans for their occurance. No new risks were discovered over the final few weeks. Over the course of the project, our team has done well to anticipate the problems and risks that the group could be faced with. Fortunately, no unknown unknowns were ever encountered. Risk management has been a helpful tool over the course of the project in helping the team have potential solutions waiting when things go wrong.
Final Project Documentation
- Include a link to your team's technical paper using the template here.
- Include a link to your team's final poster using the template here.
- Include links to final design documents as
appropriate. Copy and paste the work breakdown by
topic table from your team's project home page and place
it in this location to capture items such as:
- The final rollers were made as a shop assembly, in that most of the design was done during manufacture, and only the basic components were made in CAD.
- The final CAD model as shown above does not follow
exactly the final machine as built. Some components were
added to ensure proper functioning after the main 3D
model had served its purpose. The lead screw retaining
plate is the primary part that was never modelled. Please
see the as built machine in the construct to get details
on that component.
- Final BOM
- Manufacturing and Assembly Instructions
- Design: The barrel consists of two flange mounts, a hole for the lead screw, and a circle-cut pocket in the bottom for indexing with the die.
- Material: 4130 Steel Alloy (SMC Metal) 12” Length, 3” OD
- Machining: The barrel was cut to 10” and then reduced to a 2” OD in the “throat” section. Two flanges at the original 3” OD were kept on each end for mounting purposes.
- Wire EDM: The core of the barrel was cut using wire EDM. The diameter of the core is 0.6255”. The lead screw is 0.625” at its largest flight.
- Design: The die was designed after researching
similar injection molding dies. The angle of the
streamlined section is 60°. The “land
length” refers to the length of the final diameter
hole after the streamlined section. Extruding research
notes that the land length should be as long as 10 times
the diameter of the extrudate to reduce the amount of die
swell. A small countersink was used to
“crown” the end of the die so that the
finished extrudate would not stick or curl when coming
out of the die.
- Streamline: Stagnant areas should be avoided completely in die design. When material stagnates, it will burn and create pressure differentials that are not wanted during extrusion. Making sure there is a seamless transition between the leadscrew and the streamlined profile will avoid the creation of stagnation areas.
- Machining: The die was machined with the same 4130 stock used for the barrel. After boring the straight section .626, a countersink was made to fit the custom profile seen above. The machine shop should still have the custom tooling if a new die needs to be made.
- The 3/8 inch thick plate was cut on the waterjet so that the barrel flange would mount to both pieces of the top plate. Slots (instead of holes) were cut to mount the motor so that when the motor was bolted down, it could slide and act as a tensioner for the drive belt
- The frame is made of 8020 and was leveled by adjusting the feet on the bottom of the legs.
- Design: The rollers are made of four major components: two 3D printed base plates, a small stepper motor, and a toggle clamp. The primary function of the rollers is to pull the extruded plastic to the correct diameter and support it as it extrudes. A simple pair of door stoppers function as the rollers themselves. Two shaft couplings were made in the machine shop to attach them to the bases.
- Operation: The rollers should be adjusted to the speed and plastic that is being extruded. Gross adjustment can be accomplished by moving the mounting plate relative the 8020 and mounting plate. Fine adjustment can be accomplished by moving the toggle clamp slotted into the main base plate.
- Operator Manual
- Service Manual
In order to run the main stepper motor the following code was used. Main Stepper Motor Code