PROTOTYPE III 21st September - 27th September
This work is copyright. Apart from any use permitted under the Copyright Act 1968, no part may be reproduced by any process without the prior written permission of the user. Cover Image: Finished prototype III, Wood joinery applied to furniture, 2017.
1.3. PROTOTYPE III
Design and construction period, 21st September - 27th September Design Concept / Inspiration: • The alternative seat is inspired by Russell Hall Architect. • The design itention of this model is to reduce overall production cost and increase the speed of production. Weight:
Dimensions:
• 5.45 kg.
• 400 mm (W) x 295mm (D) x 920mm (H)
Materials: • Frame: 17mm CNC plywood and dressed recycled solid timber. • Seat and back: Corrugated metal roof sheeting. Construction process:
STRECHER
PLYWOOD FRAME
PART A.3.1
PART A.1
PART A.2
Cut stool components using CNC router. 1 hour
Retrieved components using hand router. 10 minutes
Glue stool frame using PVA glue. 10 minutes (18 hours curing time) PART A.3.2 Insert dowel pins and trim excess using japanese pull saw blade. 10 minutes
PART B.1
PART B.2
PART B.3
Select suitable solid timber 5 minutes
Dressing solid timber using thicknesser 10 minutes
Cut solid timber into length using drop saw. 10 minutes
PART C.1
PART C.2
Cut domino slot using domino joiner. 5 minutes
Glue and clamp all components till adhersive is fully cure. 10 minutes (18 hours curing time)
METAL ROOF SEAT
working with PART D.1
PART D.2
PART E.1
PART E.2
PART F.1
Measure metal roof sheeting 5 minutes
Cut roof sheeting using circular saw 15 minutes
Predrill holes along stool frame prevent delamination. 10 minutes
Install metal roof sheeting on top of stool frame. 10 minutes
Final clean up. 10 minutes
Figure 1.3.1: Construction workflow of prototype III.
Fabrication Duration:
General Comment:
Plywood frame Strecher and backrest Cut lap joint, domino and glue Metal roof seat Clean up
: 90 : 25 : 15 : 40 : 10
Total construction duration
: 180 mins + 36 hrs curing time
mins + 18 hrs curing time (PVA glue) mins mins + 18 hrs curing time (PVA glue) mins mins
39 hours (include curing time)
The group decided to use PVA glue, even though it has a longer curing time compared to foam glue. This is because PVA glue tends to be a cleaner method compare to foam glue. The standard veneer seat is replaced by a corrugated metal sheet as the material to significantly reduce the production time. This process has the same installation time but without the curing process and finishing touch up. Wood Joinery applied to furniture /
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CONSTURCTION SEQUENCES
Design and construction period, 21st September - 27th September
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2
a. Apply PVA glue on each male and female frame modules and clamp the structure together. b. Dowel pieces are inserted into predrill holes to ensure both modules are in perfect alignment. c. Excess dowel pieces have been trimmed off by chisel and hammer.
a. Both frame structure are connected by domino joint. Adhesive can be applied to further strengthen the joinery. b. Dowel pieces are inserted into predrill holes to ensure both structure modules are in perfect alignment.
TECHNICAL CHANGE: a. Instead of trimming of the excess dowel with chisel and hammer, the excess parts were trimed of with japanese pull saw blade to ensure the surfaces were not damaged during the production process.
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a. Structures are connected through dowel joint. PVA adhesive are applied throughout the surfaces to further strengthen the joinery. b. Dowel pieces are inserted into predrill holes to ensure both structures are in perfect alignment. c. Excess dowel pieces have been trimmed off by japanese pull saw blade.
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5
A
A
A
B
a. The footrest, backrest and supporting elements are connected to the stool structure through domino joints A and dowel joints B .
a. Cut the corrugated metal sheeting into 400mm x 600mm using an angle grinder*. b. Holes were predilled before screw the roof sheeting on top of the stool frame. *PRECAUTION(S):
a. Cutting any metal can be harmful if not done correctly. Metal sheeting dust an be toxic, therefore additional precaution need to be carried out during the production stage.
Wood Joinery applied to furniture /
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1.3.2
1.3.3
1.3.4
1.3.5
Figure 1.3.2: Cutting cut tabs or bridges using hand router. Figure 1.3.3: Dry-fitting the component parts before glue it all together. Figure 1.3.4: Connecting all component parts together. Figure 1.3.5: Sanding the stool modules to ensure dowel pins are flush with frame surface.
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Wood Joinery applied to furniture
1.3.6
1.3.7
1.3.8
1.3.9
Figure 1.3.6: Round the edges with hand router. Figure 1.3.7: Cutting a lap joint with handsaw and chisel. Figure 1.3.8: Clamp stool frame together until the adhesive is fully cure. Figure 1.3.9: Predrill holes along the metal roof sheeting before install it onto the frame.
Wood Joinery applied to furniture /
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Figure 1.3.10: Prototype III - Exploded diagram.
LEGENDS: 1 Corrugated metal sheeting seat. 2 Solid timber backrest. 3 Seat supporting element type 1. 4 Additional dowel joints. 5 Solid timber stretcher. 6 Solid timber footrest. 7 CNC plywood stool frame.
MATERIAL CONSUMPTION:
Prototype III - (CNC template issue date: 27th September 2017)
LEGENDS: A1 / A2 / A3 / A4
- Stool frame type B. - 20mm wastage allowance. (8mm rougher used)
1
MATERIAL EFFICIENCY - CALCULATION: Plywood sheet area : 0.775m2 Stool components : 0.262m2 Waste allowance : 0.222m2 Total plywood area (cut) : 0.484m2 Total wastage Material Efficiency
PLYWOOD FRAME
2
: 0.290m2 : 62.5%
PRODUCTION COST - CALCULATION: 17mm plywood (2.40m x 1.20m) : 60.00 Plywood sheet area (1.38m x 0.56m) : 16.00 CNC Router (per session) Number of session Total session cost
: 10.00 :1 : 10.00
Total production cost
:
AUD AUD (rounded) AUD AUD
26.00 AUD
VENEER SEAT
3
SCALE @ 1:8
1.5mm plywood (2.40m x 1.20m) : 80.00 Plywood sheet area (0.40m x 0.60m x 2) : 6.70 Total material cost : 13.40 Total manufacturing costs
: 41.80
AUD AUD (rounded) AUD
AUD (per product)
Comment and observations: Comparison to the previous two prototypes, prototype III has the lowest manufacturing costs due to the fact that the plywood veneer seat was replaced by the corrugated metal sheet (courtesy of workshop advisors). However, the prototype also has the lowest material efficiency among the others. This is because the group decided to produce all supporting elements, including, strechers, footrest and toprail by using solid timber pieces. This lead to high amount of wastage in term of CNC cutting.
Figure 1.3.11: CNC template layout - Prototype III.
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End of the report. Thank you.