CONTENTS
0 INTRODUCTION | THE BRIEF 1
// INTRODUCTION 01 // BIKE STUDY 02 // FORM EVOLUTION 04 // ITERATION 1 05 // 3D SCAN 16 // ITERATION 2 19 // PRODUCTION PHOTOS 41 We were introduced to CNC Milling to develop a timber frame inspired from the frame of a motorbike. Each student got one component of the frame to machine. The individual components, when assembled together, formed the complete motorbike frame. After this exercise, we were split into teams of 7, where each team had to develop a framework which was inspired by and evolved from the motorbike frame. The initial dimensions were fixed to be 1M x 2M x 1M. The requirement that the structure should be translatable into a habitable structural frame work made scalability a major criteria for design. The timber provided was Beech. With the supply of the timber being limited, efficiency played a significant role in the design. After the mid term crit, for which we successfully built the 1st iteration, with a few missing components, we started off with the 2nd iteration based on the comments and feedback from the analysis of iteration 1. The major roles I played were in the stock building based on the stock available, in creating the machining tool path which was the most time efficient and in the evolution of the hybrid joint in the 2nd iteration.
K E E R T H A N A V IJAYAN | 19172401 | TERM 2 | INITIAL PROJECTS PORTFOLIO BARC0059
BIKE FRAME STUDY // CLOSED FRAME // STRUCTURAL SYSTEM INDEPENDENT OF THE ENGINE // DIFFERENT ENGINE TYPES CAN BE FITTED IN // UNIVERSAL IN ITS USAGE //
CONSISTS OF ONE OR TWO SIZES OF MS PIPES WELDED TOGETHER
AFTER STUDYING A WIDE RANGE OF BIKE FRAMES WE FOUND THAT THEY COULD BE CATEGORISED INTO 2 MAJOR TYPES BASED ON THE STRUCTURAL SYSTEMS.
// OPEN FRAME // STRUCTURAL SYSTEM DEPENDS ON THE ENGINE // HIGHLY BESPOKE // LESSER FLEXIBILITY IN USAGE AS FRAMES ARE CUSTOMISED FOR EACH ENGINE // CONSISTS OF VARIED DENSITY AND MATERIAL SECTIONS
K E E R T H A N A V IJAYAN | 19172401 | TERM 2 | INITIAL PROJECTS PORTFOLIO BARC0059
0 2
0 3 This was the form which was chosen. It is derived from a closed frame structure.The interesting feature of this structure is that the arc increases the internal volume of the space.
Based on the analysis of the motorcycle frame a few stick model iterations were done to obtain the basic structural wireframe. Using this, we could study the connections between members and the basic forces and the directions they acted in, on each member. Based on this model we could calculate the number of nodes which required solutions.
STICK ANALYSIS K E E R T H A N A V IJAYAN | 19172401 | TERM 2 | INITIAL PROJECTS PORTFOLIO BARC0059
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// The arc branches into 2 stands which touches the ground
// stands moved wider apart to achieve more internal space.
// the arc increases the volume inside the structure and it also provides the tension which helps hold up the horizontal member.
// the horizontal member is connected to the triangle
// initial sketches derived from the bike frame with supports extending to the ground.
Basic sketches were made by creating a line diagram of the bike frame and then extending the ends for support from the ground. These were then developed in proportion and with functionality in mind to get to the final wire frame.
// one point contact in the ground where the arc and the lower braces meet.
SIDE ELEVATION
// the width was extended sideways to increase the internal space.
FORM EVOLUTION from bike frame PLAN
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K E E R T H A N A V IJAYAN | 19172401 | TERM 2 | INITIAL PROJECTS PORTFOLIO BARC0059
MODEL RHINO
COMPONENTS
EXPLODED CLOUD
1250
CONTINUOUS ARC
1000
TRIANGLE NOTCH THE EPSILON 0750
STANDS
HORIZONTAL MEMBER 0500
STIFF TRIANGLE
TRIPOD TIP 0250
0000
0M 25
250MM
M
250MM
POINT
EM12 | EM6 | BN6 : // TOOLS TO MANUFACTURE
CNC CROSS LAMINATION COLD BENDING : // PRODUCTION METHOD
09 : // MACHINED COMPONENTS
10 : // NUMBER OF COMPONENTS
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1500
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0 7
The arc was made continuous by cold laminated bending of 3mm strips. Addition of so many layers of glue made the member super strong. The cold bending resulted in very minimal spring back.
The front part consists of the stiff triangle and the tripod tip. The triangle is extended on the sides to receive the horizontal and tripod members. The horizontal member slides into the triangle from the sides. The tripod tip also follows the sliding mechanism from the bottom but to prevent the member from sliding down there was an increase in the volume of the ends of the extension.
At the rear end the horizontal member is slotted into the stands. This restricts the sideways movement of the horizontal member. The volume of the stand is increased to receive the horizontal member. The arc was just placed on the stands as the epsilon piece wasn’t ready. But the structure still proved to be stable due to its self weight and rigidity of the joints.
JOINT BETWEEN MEMBERS K E E R T H A N A V IJAYAN | 19172401 | TERM 2 | INITIAL PROJECTS PORTFOLIO BARC0059
ALONG THE GRAIN
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AGAINST THE GRAIN
TIMBER BENDING STUDY K E E R T H A N A V IJAYAN | 19172401 | TERM 2 | INITIAL PROJECTS PORTFOLIO BARC0059
COLD BENDING TRIAL 1 WITH 3MM PINE STRIPS
Based on the trials, we found the optimum size for cold bending to be 3 mm. Hence we cut strips of 3mm thk beech. A template for bending was made. Only the positive mould was made. For the negative part, small blocks of timber were used. The cold lamination was done layer by layer. 5 layers were done at a stretch and once the glue had dried, the next set of layers were added.
STRIPS FROM THE STOCK
Even though the desired shape was attained and the strength was also high, due to the glued layers, the wastage was enormous. For every 3mm strip cut, there was an equal amount of wastage due to the blade width. It was not time efficient either as it took nearly a day to get the strips cut. These issues made scalability nearly impossible.
5
4
2
3
1
CHOREOGRAPHY OF CLAMPING CURVE
FLAT
CURVE
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1 0
TRIPOD TIP MACHINING The three members of the tripod tip were machined in one single stock. The gap between each member was just twice the tool size used - EM12. There was still a considerable amount of wastage on the outer side.
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1 1
PIN LOCATION MODEL STOCK LASERCUT ZIG
TABS PIN LOCATIONS
TRIANGLE STOCK BUILDING To reduce wastage and also strengthen the member, a cross laminated stock was prepared. The stock comprised of 3 layers. The layers were cut precisely and assembled with the use of a laser cut template and dowels to hold the layers in position. The tabs, to locate the pins for flipping, were placed at the corners of the triangle. Being a rectangular section, the stock wasn’t made bigger than the actual size required in order to avoid wastage.
LAYER 1 AND 3 K E E R T H A N A V IJAYAN | 19172401 | TERM 2 | INITIAL PROJECTS PORTFOLIO BARC0059
LAYER 2
The form needed for the structure could only be achieved when it was machined from two sides. The cross laminated stock was prepared keeping in consideration the location of the tabs and pins so that it could be flipped and machined over again. The form being a triangle, there were 3 tabs in each of the edges and 4 pins to fix it after flipping. First the stock was fixed on the sacrificial material with screws which were calculatedly placed on the tab region so that they were not machined off.
1 2
FOUR PINS WERE USED TO FIX THE STOCK TO THE SACRIFICIAL WHILE FLIPPING. FOR ADDITIONAL STABILITY, STRONG GLUE WAS ALSO APPLIED IN THE TAB AREAS.
EM12
BN6 TABS WERE ADDED FOR LOCATING PINS AND FOR STABILITY OF THE STOCK WHEN FLIPPED.
TRIANGLE MACHINING K E E R T H A N A V IJAYAN | 19172401 | TERM 2 | INITIAL PROJECTS PORTFOLIO BARC0059
1 3 A simple geometry whose size slightly increased its complexity. Hence this piece also was machined in the PIRANHA. The placement of the stock was the trickiest part as it didn’t fit in straight. The stock was then fixed diagonally and both the members were machined at the same time. To achieve this, the CNC bed of the PIRANHA was also modeled with precise dimensions and the stock was fixed on the sacrificial based on the dimensions from the model.
POCKET EM12
STEEP AND SHALLOW BN6
PLACEMENT OF STOCK IN THE PIRANHA
HORIZONTAL MEMBER K E E R T H A N A V IJAYAN | 19172401 | TERM 2 | INITIAL PROJECTS PORTFOLIO BARC0059
1 4
HAAS MACHINING - BY ANN
THERE WAS ADDITIONAL STOCK ADDED ONLY IN THE CENTER FOR THE BULGING AREA WHICH RECEIVES THE HORIZONTAL MEMBER
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STAND
FINAL ASSEMBLY | ITERATION 1
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1 6
SCANNING CREOFORM | FERRO
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1 7 TRIANGLE RHINO MODEL
CREOFORM SCANNED MESH
TRIANGLE SCANNING-
CREOFORM
The deviation found in individdual member scanning was very minimal - less than 5 mm. The only problem with the analysis using the creoform is that the placement of the scan on the model member is done manually and this causes a lot of deviation.
K E E R T H A N A V IJAYAN | 19172401 | TERM 2 | INITIAL PROJECTS PORTFOLIO BARC0059
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DEVIATION ANALYSIS-
FERRO
The main deviation was caused because of the missing member which wasn’t machined. This caused a circular motion of deviation. There was a maximum deviation of 100 mm.
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TRANSITION-
ITERATION 1 TO2
Even though the structure was STABLE in iteration 1, there were a few modifications necessary to increase stability and scalability. The stiff triangle was changed to the bottom triangle which touched the ground. This helped in the load to be dispersed evenly. The horizontal surface created by the horizontal member was also lifted higher in the process. The horizontal members were moved inwards so that they interlocked with the new triangle. In the previous iteration it would slid out easily and could cause a failure of the entire structure.
K E E R T H A N A V IJAYAN | 19172401 | TERM 2 | INITIAL PROJECTS PORTFOLIO BARC0059
2 0
The spine was made into 3 components to make it more efficient for manufacturing.
200mm
200mm
The frontal nose, where the spine, stiff triangle and the tripod tip met in the first iteration, was totally altered. The joints were moved apart instead of meeting at one point. A trident was created which held the spine, triangle and the brackets.
The Stands were made more narrower and wider in certain areas to allow the horizontal member to slide in and lock itself at one place. It was made into one single member which was connected to the spine with a notch joint.
On the other end if the horizontal member the stands were slotted into the horizontal member which restricted the movement in all directions.
TRANSITION-
ITERATION 1 TO2
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2 1
Arc
Trident Horizontal member Stands
Triangle
m
COMPONENTS-
0m 20
200mm
Brackets
ITERATION 2
200mm
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2 2
EXPLODED MEMBERS -
ARC
The arc was a continuous member in iteration 1 but resulted in a lot of wastage. Hence the arc was broken down into 3 parts. The joint and the bending were combined. A hybrid joint was evolved. The front curve was done using steam bending. The spring back of the bending provided the tension which locked all the components in place.
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2 3 HYBRID JOINT EVOLUTION
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The cutting of the fingers was done using a table saw. The spacing and the finger thicknesses were calculated based on the thickness of the blade. The circular blade left an arc in the end which was later removed using a band saw. This resulted in imprecise cuts. CUTTING USING A TABLE SAW
FINGER JOINT TRIAL 1
FINGER JOINT EXPLORATION The clamping was done from one end to the other, which lead to one end being locked, which in turn restricted the movement of sliding into the fingers thus resulting in cracking. There was nothing stopping the member at the ends, causing the member to slide and resulting in the solid block ending up at the curved section. There weren’t too many calculations done other than the calculation of the thicknesses of the gap and the fingers. In trial 1, the members were cut in an angle at the end to compensate the length of each member along the curve.
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FINGER JOINT TRIAL 2
2 4
2 5 STEAMED ASH STRIPS 3MM THK
There were failures in the previous iterations due the rigidity in the members. There was always one side which was fixed and this reduced the allowance for the fingers to slide inside. To overcome this, a hybrid joint was created. Steamed Ash strips were introduced in between the fingers. These strips connect the 2 members. CNC MILLED BEECH MEMBER 1
The finger cuts were done using CNC for maximum precision and were cold bent.
3.5mm gap 3mm fingers
HYBRID JOINT 1 CNC MILLED BEECH MEMBER 2 3.5mm gap 3mm fingers
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2 6
The curve in the mould was made precise to enhance the difference between the curve and the straight section. This was done using a laser cut template of the curve.
A metal strip was cut to the length of the members put together with few mm extra to give room for the fitting. To the ends of this, wooden blocks were fixed. The metal strip dispersed the force uniformly and the wooden blocks helped in holding the members in position without sliding off while clamping.
BOTH THE MEMBERS FOR THE ITERATION WERE MACHINED FROM A SINGLE BLOCK TO REDUCE WASTAGE. 2 MM OF STOCK WAS LEFT AT THE BOTTOM TO HOLD THE FINGERS TOGETHER AND PREVENT VIBRATION WHILE MACHINING. THIS WAS LATER CUT OFF USING A TABLE SAW.
HYBRID JOINT-
BENDING PREPARATION
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2 7
CHOREOGRAPHY OF CLAMPING
Based on multiple trials and iterations we figured out the clamping process. After the first two clamps are fixed the rest of the clamps follow a very specific choreography to allow the members to slide in and lock in place.
K E E R T H A N A V IJAYAN | 19172401 | TERM 2 | INITIAL PROJECTS PORTFOLIO BARC0059
2 8
TOP SIDE.
BOTTOM SIDE.
HYBRID JOINT- ITERATION 1
THE TINY GAPS WERE CAUSED DUE TO THE MISTAKES MADE IN THE CUTS ON THE ENDS OF THE FINGERS.
K E E R T H A N A V IJAYAN | 19172401 | TERM 2 | INITIAL PROJECTS PORTFOLIO BARC0059
// CREOFORM SCANNING HYBRID I1
// RHINO MODEL - ASH SRTIPS
// RHINO MODEL - CNC MILLED BEECH 1
// RHINO MODEL - CNC MILLED BEECH 2
HYBRID JOINT- ITERATION 1
OVERLAY OS SCAN AND MODEL
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2 9
To make it more efficient, the ash strips were made thicker as they were steam bent. This resulted in a lesser number of fingers. This also enhanced the scalability of the joint.
HYBRID JOINT ITERATION 2
Scan of hybrid joint 2
CNC milled beech members with 7.5mm slots and 3 mm thk fngers
7mm thk steamed ash strips
3 0
K E E R T H A N A V IJAYAN | 19172401 | TERM 2 | INITIAL PROJECTS PORTFOLIO BARC0059
3 1
The clamping process was similar to the previous iteration. Polyurethane glue was used. This helped in the smooth sliding of the members. As there was a steamed member, which tended to be wet, PU glue was preferred.
CHOREOGRAPHY OF CLAMPING
HYBRID JOINT 2
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3 2
The ends of the fingers were precisely calculated using Rhino and were milled to perfection. The angle of the cut varied in each of the fingers because of the curve.
REVISIONS MADE - HYBRID
The part where the beech and the ash meets were rouded for proper fitting and ease of sliding.
JOINT 2
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3 3
COMPLETED MEMBER -
HYBRID JOINT 2
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3 4
TRIANGLE |
JOINT EXPLORATION
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3 5
TRIANGLE |
STOCK BUILDING
The stock of the triangle consisted of 3 layers. A thin additional layer was added on the specific area where it was needed. To match that, an additional stock was added on the tab regions. The top layer of the stock was from a bent strip. We wouldn’t have been able to use the strip if it was planed on both sides as the thickness would have reduced below the required thickness. Hence it was planed at the bottom while the top was left unplaned. This saved us 5 mm, which when arranged accordingly saved us from adding an additional 4th layer.
K E E R T H A N A V IJAYAN | 19172401 | TERM 2 | INITIAL PROJECTS PORTFOLIO BARC0059
3 6 TP1 EM20
TRIANGLE |
MACHINING
As the top layer was not planed, the origin had to be set by measuring it manually. An additional toolpath was done to make the tabs levelled.
TP2 BN20
TP4 BN20
TP3 EM20
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3 7
TRIANGLE |
TABS
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3 8
TRIANGLE |
TABS
During the machining all the tabs were chipped off because of the high speed. Additional pine memberswereglued on topof the chipped off tabs. An additional toolpath was created to level these tabs before flipping.
K E E R T H A N A V IJAYAN | 19172401 | TERM 2 | INITIAL PROJECTS PORTFOLIO BARC0059
3 9
TRIANGLE |
FLIPPING
After the tabs were levelled the piece was flipped along the y axis and anchored to the sacrificial member with help of pins. For additional safety, quick dry industrial glue was used in the tab areas to make it fixed firmly.
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4 3 0 7
TRIANGLE |
FLIPPING MACHANISM
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4 1 TRIANGLE |
SIDE 1
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4 2 TRIANGLE |
SIDE 2
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4 3
DOWELS
WEDGES
They were used to align the stock layers
After the stock preparations, there were a lot of gaps due to some mis-alignment and imperfect cutting. These wedges were inserted to fill the gaps.
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4 4
LAYERING
SMALL TABS
The cross lamination created a beautiful amalgamation of different directioned grain.
During machining on the flipped side, one of the tabs entirely broke. The tabs were small and had to take the full vibration caused by the machine as well as the load of the member itself. After we realised this, we placed some wedges underneath the member before the start of machining to absorb the vibration. This saved the piece from getting destroyed.
K E E R T H A N A V IJAYAN | 19172401 | TERM 2 | INITIAL PROJECTS PORTFOLIO BARC0059
4 5
TOP NOTCH The smooth concave part where the trident gets locked in. These images shows the only fully survived tab.
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4 6
SIDE NOTCH The part where the side brackets gets attached to the triangle
K E E R T H A N A V IJAYAN | 19172401 | TERM 2 | INITIAL PROJECTS PORTFOLIO BARC0059
4 7
SCOOPS The scooping was done in the member in order to receive the horizontal member. Each side had 2 scoops.
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K E E R T H A N A V IJAYAN | 19172401 | TERM 2 | INITIAL PROJECTS PORTFOLIO BARC0059
THANK YOU
K E E R T H A N A V IJAYAN | 19172401 | TERM 2 | INITIAL PROJECTS PORTFOLIO BARC0059