References ROBOTIC PROTOTYPING  Bespoke Digital Fabrication
 Design and assembly of lightweight metal structures Gramazio Kohler Research, ETH Zurich 2014-2018  Additive Fabrication
 Additive Robotic Fabrication of Complex Timber Structures, Zurich, 2012-2017.  Carbon Fiber Wiring
 ICD/ITKE, Pavilion, Stuttgart, 2014.
The spread of multi-functional industrial robots has had exponential acceleration in the last decade that it has become a standard tool in many industries, where automation, efficiency and accuracy are the heart of the production process. Since the ‘80s, with the development of information and computational technologies, the machines begin to be controlled through digital tools defining the beginning of a new paradigm in which the virtual world and the physical world come together and influence each other, drawing the foundations for the emergence of new processes and production strategies. The development of these technologies does not occur evenly in all disciplines and production companies but condenses on specific sectors, such as automotive and aerospace, going to redefine the quality standards of their respective sectors. The birth of these machines is the result of a need of greater control over the production process and greater automation, elements not necessarily connected with the world of construction and architecture. The diffusion of industrial robots in these fields occurs in manners much slower and gradual as for digitization, because of an industry in which the development timings and implementation medium assume different sizes and durations, a much more fragmented and complex industry.
Very significant reason is also a limited and well-established design methodology and dominant constructive that has not evolved with the same speed of other disciplines; in defence of this, it is the fact that the architectural project encloses a more difficult to calculate or in some cases of not calculable variable number that can not be foreseen in advance and then inserted in a fully automated process, but they provide, at least for now, the presence of the human factor as an element of conjunction with the real world, able to use intuition and take charge of the major design decisions. Despite a more gradual evolution of the last decade we have seen a substantial increase in the use of robot technology both within the construction process and within the design phase. The flexibility of robots such as industrial arms provides a wide spectrum of potential uses, not limiting them to unique automation tools predetermined and finite processes, but added elements able to expand the possibilities of the designer. 1Fabio Gramazio and Matthias Kohler, The Robotic Touch: How Robots Change Architecture, Research ETH Zurich 2005-2013.
ENDEFFECTOR DESIGN ROBOTIC PROTOTYPING Pneumatic gripper The fabrication process has been exploited through the use of robotic technology in collaboration with manual operations. The robot which has been used is a Nachi MZ07 which provided the fabricaiton constraints in terms of profile lenghts. The robotic arm has been utilized in combination with a pneumatic gripper SMCHL2-20D as operating tool. The gripper has been actuated through a solenoid valve activated by the digital output signal of the robot G-Code.  Nachi MZ07
The fabrication sequence is divided into four main moments: Bespoke cut of discrete elements: the segments are pre cut with custom lengths according to the global model then positioned within the station to allow the robotic arm to record the position and automate the gripping process throughout the sequence. The longest element of each node has been positioned first in the central holder leaving to the robot the spatial orientation only. Gripping: a pneumatic gripper (SMCMHL2-20D) has been utilised. The actuation of the tool happens through the digital output of the robot; the connection end-effector / digital output allows to have the gripping process indipendent from an external controller or actuator, increasing the consistency and reliability of the whole process. Spatial positioning: the segments are gripped, positioned and oriented in place according to the network configuration. The positioning sequence has calculated in a way to avoid collision with the previously assembled elements within the node itself. Assembly: the segments are assembled togheter with PVC plates with finger joints connection. Because the thermoformable proprieties of the material, each plate is heated and formed on the go according to the geometric conditions of the node. This method allows to not rely on any precalculation of each plate angle, increasing consequently the fabrication speed and simplifing the whole manufactoring process. Main objective has been to keep the sequence as consistent and solid as possible as well as simple, with the aim of a full automated assembly process. The sequence developed is mostly scale indipendent and could be migrated to bigger robotic arms for a 1:1 application. Three different materials have been tested for the node plates: acrylic, PVC and polyethilene. PVC turned out to be the most reliable in terms of bending capacities when heated and stiffness after drying down.
 Bespoke cut of timber segments according to the global geometry
 Gripping of the timber profile in station position.
 Spatial orientation of the profile according to the node angle.
1:1 Prototype node The fabrication sequence considered was meant to guarantee speed and simplify the node assembly process. Thermoformable plastics were considered because their ability to reshape when heated; plastic plates with finger joints connection were heated and formed throughout the assembly process as a way to solve complex node conditions with custom angles in space. Three different types of thermoplastics were tested: acrylic, polyethylene and PVC. Load tests have been executed on each of them before and after heating resulting in the utilization of PVC as main node material because the load bearing capacities and flexibility.
References for finger joint 3d-nodes and complex hull bolder node.
 1:1 Prototype segment The segments timber profile was tested into 3, 3.5 and 5 configuration; the 3 cm profile was observed to be stiff enough and the most lightweight for the prototype purpose.
 Image 01 Irregular connection node, finger jointed paper. AAG Zaha CODE
 Image 02 Convex Hull node construction, CITA Rise Project.
Polymethyl methacrylate (acrylic glass) Poly(methyl methacrylate) (PMMA), also known as acrylic or acrylic glass as well as by the trade names Plexiglas, Acrylite, Lucite, and Perspex among several others (see below), is a transparent thermoplastic often used in sheet form as a lightweight or shatter-resistant alternative to glass.
 Polypropylene (PP) Polypropylene (PP), also known as polypropene, is a thermoplastic polymer used in a wide variety of applications including packaging and labeling, textiles (e.g., ropes, thermal underwear and carpets), stationery, plastic parts and reusable containers of various types, laboratory equipment, loudspeakers, automotive components, and polymer banknotes. An addition polymer made from the monomer propylene, it is rugged and unusually resistant to many chemical solvents, bases and acids.
 Connection detail node plate catalogue.
 Polyvinyl chloride (PVC) Polyvinyl chloride, more correctly but unusually poly(vinyl chloride), commonly abbreviated PVC, is the world’s third-most widely produced synthetic plastic polymer, after polyethylene and polypropylene.4 PVC comes in two basic forms: rigid (sometimes abbreviated as RPVC) and flexible. The rigid form of PVC is used in construction for pipe and in profile applications such as doors and windows.
 Material to be tested as potential node plate.  MATERIAL TESTING
 Material load test. Top to bottom Acryl Glass, Polypropylene, Polyvinyl Chloride.
 Material post load test. Top to bottom Acryl Glass, Polypropylene, Polyvinyl Chloride.
Soft wood rofiles Timber soft wood profiles has been used as a main structural material due to its convenience in fabrication process and physical properties. Geometrically there are 2 different types of profiles, triangulars and quads. Both quad and triangular profiles has been tested in 2cm, 3.4 cm and 3 cm sizes to evaluate the best fit for the global model. In terms of fabrication proces,as quads were more staightforward, manufacturing triangular pieces had some constraints.They were cutted from quad pieces and edges of the triangle were drawn on the face of the profile to adjust the angles of the table saw. In order to maintain the equal angle, this process continiued for each triangular members.
 Profiles used in study models. Left to right 3.4cm, 3cm, 3cm, 2cm, 2cm.  Prototype for each profile thickness. Top to bottom 3.4cm, 3cm, 3cm, 2cm, 2cm.
 3x3cm PROFILE cube skeleton + membrane
 3x3cm PROFILE TETRAHEDRAL skeleton + membrane
 3x3cm PROFILE CUBOID skeleton + membrane
Topological and geometrical description ROBOTIC PROTOTYPING
The topology of the prototype was meant to demonstrate the structural and spatial features of the system. The geometry was conceived to have a front part showing a potential facade/enclosure strategy made with cling film wrapping and an open ended part which suggested the possibility to expand the system into a full scale architectural object. Symmetry along the x-axis was considered as a way to have a global better stability and reduce the number of custom elements. Closed loops were meant on the y-direction also to improve stability and propagate deviations due to the fabrication process in a more even way.
 Polyhedra packing with interpolated segment connections as regular rods.
 From polyhedra packing to center node geometry and mesh to be regularized.
PROTOTYPE SPECIFICATIONS Bounding Box Dimensions: 307.8x125.8x223.5cm 28 x Nodes 342 x Connecting Strips 126 x Segments (12 Quad Profile, 114 Triangular Profile) 27.47 m wood (Quad 3x3cm, Regular Triangel 3cm Sides) 2052 x 6x1/2” Wood Screws Production Time: 18h40min Total Weight: 34 Kg