The main thread, the bearing and all the screws used are the following:
A total of one pillow head bearing, 3 M8 nuts, 15 M5 nuts and 15 M5 Parker screws were used.
As for the assembling itself, the first step consists on placing the rails over the base and the moving jaw over the rails (the moving jaw could already have the bearing put on), being careful on selecting the correct orientation for the rails. It is kind of intuitive so it should not go wrong. At the same time, the nut box and the fixed jaw can be placed on the ends of the base as it can be seen in the picture.
Then, all the M5 screws needed can be used to join the parts to the base. After this is done, the main thread should start entering into the nut box, and before it reaches the bearing from the moving jaw, the mut box cover should be placed. When the main thread is properly inserted into the bearing, its screws should be tightened. The nut box and its cover should also be tightened.
Lastly, the C-shaped component should be placed at the end of the base with a special shape (you will know which one we are referring to).
The design is quite self-explanatory, specially if you have the photo of the assembly by your side. If you see an hexagonal moulding, an M5 nut should go there. There is only one bigger moulding, which is of course for an M8 nut (the other tho M8 nuts go inside the slots of the rubbers).
First, each component is designed in the Fusion 360 software, using commercial bench presses as reference. That's also the case for the dimensions of our 3D printed bench press.
One of the challenges of our design was to ensure smooth movement for the shaft and tight joints between components. With that in mind, a pillow block bearing was added to the design and multiple holes for M5 and M8 screws. The 3D model also include hexagonal-shaped mouldings, where nuts are inserted in order to tighten the joints.
A C-shaped component was added later to press the bench press against a table. This component includes 2 handles and cushions to fulfill its mission.
The 3D printing process starts using CREALITY Ender 3 printers. Recommended printing parameters for Ender 3 were chosen: bed temperature 60ºC and extruder temperature 210ºC. Also, default layer height was 20 mm and infill density chosen was 20%.
Rails
The first components printed were the rails.
Plate adhesion type: Skirt
The printing process of the rails lasted 5 hours and 49 minutes.
Total weight: 115 grams.
The resulting part is shown next.
Fixed Jaw
The second component printed was the fixed jaw. It has the same parameters than the rails (which is the case for almost every component).
Printing time was 3 hours and 20 minutes.
Total weight: 78 grams.
The final product is shown next:
Handles
Three handles were printed at the same time. One for the main thread and the other two for the C-shaped component.
Plate adhesion type: raft.
Total printing time: 1 hour and 30 minutes.
Total weight: 17 grams.
Cushions
A first iteration of the design is shown.
The cushions were redesigned when the deadline was approaching. The hexagonal moulding was replaced by a slot in order to avoid displacements of the nut.
Plate adhesion type: raft
Total printing time: 1 hour and 24 minutes
Total weight: 18 grams
Moving Jaw
Plate adhesion type:
Total printing time: 3 hours and 20 minutes.
Total weight: 70 grams.
Base
Initially, the base was just a solid block component, but it was so big that it didn't fit in the printer's bed, so it had to be divided into 2. Also, a hole was made in the center in order to reduce printing time.
Plate adhesion type: Skirt.
Printing time was 6 hours and 3 minutes. Total weight: 123 grams.
C-shaped support
Plate adhesion type: Skirt
Total printing time: 3 hours and 13 minutes
Total weight: 36 grams.
Nut thread box (and cover)
Box and cover were printed at the same time
Plate adhesion type: Raft
Total printing time: 3 hours and 27 minutes
Total weight: 42 grams.
We realized that a hole was missing on the cover part, so it had to be redesigned and reprinted. Also, covers for the nuts were needed.
nicolas.rodriguez.2
