Sinds de komst van de computer zijn de ontwerpmogelijkheden sterk toegenomen. De vertaling van het ontwerp gebeurt echter nog vaak via plannen, die dan op de werf met traditionele bouwmethoden worden uitgevoerd. Al de informatie die digitaal beschikbaar is gaat als het ware verloren bij deze stap. Digitale fabricatie brengt hier verandering in, door een directe verbinding te maken tussen het ontwerp en de productie. Het reëel object is als het ware een exacte kopie van het virtueel model. SPIF staat voor Single Point Incremental Forming. Door met behulp van een industriële robot het metaal geleidelijk aan in te duwen volgens een bepaalde gereedschapsbaan (toolpath), is er een grote verscheidenheid van geometrie mogelijk. Aangezien er geen mal nodig is voor dit proces, is het ideaal voor prototyping. Ook in architectuur is deze ontwerpvrijheid uiteraard een grote meerwaarde. Via één of meerdere test cases zou ik de mogelijkheden van deze techniek in een architecturale context willen onderzoeken. Mogelijke toepassingen zijn bijvoorbeeld een zelfdragende gevel of een dakconstructie die door zijn geometrie geen dragende onderstructuur meer nodig heeft. Gebaseerd op een bestaand project van een carport, heb ik als voorbeeld een structuur gemodelleerd en onderworpen aan een bepaalde belasting. In het tweede geval is op dezelfde geometrie een grid van ribben toegevoegd, en duidelijk is dat de doorbuiging aanzienlijk verbetert. Aangezien het een integraal proces van ontwerp tot productie is, lijkt het me interessant om dit binnen één software af te handelen. Zo heb ik getracht om het toolpath, nodig om de robot aan te sturen, ook binnen Grasshopper te genereren. Als output geeft dit een reeks met coördinaten en richtingsvectoren. Na het structureel optimaliseren van het ontwerp en de vertaalstap naar de robot-instructies, kan de productie beginnen. Als laatste aandachtspunt zullen de afzonderlijke elementen moeten geassembleerd worden, zodat zij werkelijk functioneren als één geheel. Gert-Willem Van Gompel Master in de ingenieurswetenschappen: architectuur

1. Digitale Fabricatie
SPIF
Gert-Willem Van Gompel
Master in de ingenieurswetenschappen: architectuur
Promotor: Vande Moere Andrew
Corneel Cannaerts (ir. arch.)
Marc Lambaerts (FabLab, dep. Werktuigkunde)
Matthias Mattelaer (DMOA, ir. arch.)
Hans Vanhove (dep. Werktuigkunde)22 oktober 2015

2. Ontwerp Productie
Waarom digitale fabricatie?

3. Ontwerp Productie
Waarom digitale fabricatie?

4. Missing Link
tussen ontwerp en productie
Ontwerp Productie
Waarom digitale fabricatie?
doel thesis:
volledig digitaal proces in een bepaalde testcase doorlopen
zowel digitaal, parametrisch ontwerp en optimalisatie als digitale fabricatie
onderzoeksvraag:
Hoe kan Single Point Incremental Forming geïntegreerd worden binnen de context
van een digitaal ontwerp- en productieproces?

5. Wat is SPIF?
Figure 17: Single Point Incremental Forming of a cone.
Kim & Park [70] focused their attention o
anisotropy on formability. For this pu
measurements of the major and the m
carried out both along the rolling direct
transverse one (TD). The tests wer
pyramid specimens with a varying too
material was the aluminium alloy 1050-O
σο = 33MPa, R0 = 0.51, R45 = 0.75, R
concluded that formability along the trans
greater when small diameter tools are ut
the rolling direction it is larger with large d
In order to fully understand the increase
AISF, a simple FEM was developed by
and Bambach et al. [69]. They found tha
step size, ∆z, the strain increments impo
decrease and any point is overlapped ot
while strains increase with increasing
from a stress point of view, a negat
distribution is observed under the tool a
elements; in this way, the tool action p
fractures during the process, until the too
with the sheet. Finally, at decreasing ∆z
along the wall decreases too, so that a h
can be imposed without tears occurring.
Nontraditional Forming Limit Diagrams
Forming limit diagrams usually have the
shown as FLC in conventional formin
Εmax, FLDo
3.5
Jeswiet, J., Micari, F., Hirt, G., Bramley, A., Duflou, J., & Allwood, J. (2005). Asymmetric single point incremental forming of sheet metal.
Cirp Annals-Manufacturing Technology, 54(2), 623-649.
oints to generate new, virtual target geometry. This virtual
art geometry forms the basis for the determination of an
mproved toolpath. Using a scale factor of 0.7 was found
provide optimal results for part made of DC04, 1.5 mm.
V shaped
tub
mbrogio et al. [106] use an in-process measurement
stem that allows the determination of deviation between
e anticipated intermediate part geometry and the actually
alized intermediate shape. Per layer (incremental
olpath contour) the observed deviations are measured to
orrect the toolpath geometry for the next contour.
ConeCross Hexagon
he proposed system has been tested with a discrete point
ontact measurement system, used interactively, thus
mulating the availability of real in-process measurement
quipment. The toolpath optimization algorithm has been
sted with pyramid part geometry. The author claims
gnificant accuracy improvements. No quantitative output
however available to evaluate the achievable
mensional accuracy.
HyperbolaDome
5 lobe
shape
EXAMPLES OF APPLICATIONS
he major advantage of asymmetric incremental forming is
can be used to make asymmetric parts, quickly and
conomically, without using expensive dies. Shapes used
demonstrate the abilities of the process are shown in
able 8. Some of the shapes illustrated have been used to
onduct springback experiments, and in determining the
aximum draw angle φ, others are just for demonstration
process abilities.
he asymmetric single and two point incremental forming
ocesses are still in their infancy. Much research work
mains to be done and to do this appropriate shapes are
Table 8: Shapes used to demonstrate the viability of the
process and for experiments.
oven cavity for use in developing country applications. The
last two are for the same manufacturer of custom
motorbikes; the first part is for a motorbike seat and the
second is part of a gas tank.
5.2 Custom manufacture of a solar oven
Truncated pyramid
Faceted
cone
Multi-shaped surface

6. Wat is SPIF?
Fig. 5 Top DSIF Method A with a forming tool and a support tool. Bottom DSIF Method B with
two forming tools
40 A. Kalo and M. J. Newsum
Fig. 9 A component with performative textures and features
44 A. Kalo and M. J. Newsum
Kalo, A., & Newsum, M. J. (2014). An Investigation of Robotic Incremental Sheet Metal Forming as a Method for Prototyping Parametric
Architectural Skins. Robotic Fabrication in Architecture, Art and Design 2014, 33-49.

7. Wat is SPIF?
Kalo, A., & Newsum, M. J. (2014). An Investigation of Robotic Incremental Sheet Metal Forming as a Method for Prototyping Parametric
Architectural Skins. Robotic Fabrication in Architecture, Art and Design 2014, 33-49.
Fig. 10 Comparison of overall geometric improvements with the ‘ribbing’ system
An Investigation of Robotic Incremental Sheet Metal Forming 45

8. With the process combination of stretch forming and ISF the forming of global shape and local
features can be performed in an integrated procedure (see Fig. 3).
Figure 3: a) Clamping the sheet blank; b) Generating a preform with stretch forming; c)
Forming details and features with ISF
Compared to pure ISF, the process combination allows for a shorter process time as well as
improved geometrical accuracy and sheet thickness distribution [9]. Compared to pure stretch
forming, the process combination enables the realization of changes in curvature within one panel
geometry and the generation of features, such as the described cones.
Production Routine and Tooling Concept
The tooling concept for the described production approach is a combined die for the stretch
forming and the incremental forming process. Due to the low forming forces in ISF, the use of very
cheap tool material for a die is possible. This way a bonded block of medium density fiberboard
(MDF) has been prepared for the milling of the customized dies. However, the MDF block deforms
under the high pressure induced by the stretch forming, but due to the homogenous structure of
MDF, these deformations are uniform and can easily be taken into account in preliminary
simulation of the process.
The tooling concept is illustrated in Fig. 4 and the steps of the production routine for the
freeform panels are the following:
1) Milling of the die (based on a prepared MDF block)
2) Stretch forming of the first outer layer
3) Trimming of the first outer layer
4) For an optional second outer layer, the steps 2 and 3 will be conducted twice
Figure 6: Produced and joined freeform panel: Smooth outer layer (left); Structural layer (right)
The entire assembled prototype structure is presented in Fig. 7 and serves as proof for th
ducibility as well as the mountability of the panels.
Figure 7: Assembled prototype structure with 8 panels (4 different panel shapes)
Case Study
In order to assess the applicability of the proposed panel system for large-scale applications, a
further case study has been investigated by means of design and structural analysis. The developed
case study is a shell spanning over four foundation points, which build a square of 8.15 m by
8.15 m. The maximum height at the apex is 4.80 m.
Figure 8: Case study design for a large-scale freeform structure
The construction results in 100 panels with a constant effective thickness of 150 mm. To produce
all panels, a die block with a height of only 650 mm is necessary. Due to the double symmetric
Key Engineering Materials Vol. 639 47
Wat is SPIF?
Bailly, D., Bambach, M., Hirt, G., Pofahl, T., Della Puppa, G., & Trautz, M. (2015). Flexible manufacturing of double-curved sheet metal
panels for the realization of self-supporting freeform structures. Key Engineering Materials, 639, 41-48.

9. Toepassingen?
Project 2XmT by Christopher Romero, Nicholas Bruscia (self-structuring and lightweight architectural screens from sheet metal)
http://blog.archpaper.com/2013/07/reinventing-the-facade-skin-competition-names-four-first-stage-finalists/#.VifKmxDhCAx

10. Toepassingen?
Eventueel toepassing binnen huidig of toekomstig project van DMOA

11. Toepassingen?
© Otto Wöhr GmbH, Friolzheim
http://brunier-ernst.com/Design-Carport

14. beschrijving van het toolpath eventueel integraal in Grasshopper genereren
(alles binnen één softwarepakket)
Toolpath

15. output: lijst met coördinaten en richtingsvectoren
Toolpath

16. Definiëren van verschillende test cases met als doel de
verschillende productiestappen te tonen.
1. Parametrisch ontwerp
structurele optimalisatie uitvoeren op bepaalde geometrie
spanningen/doorbuigingen minimaliseren
2. Vertalen
3D model vertalen naar robot-instructies
toolpath laten genereren
3. Digitale productie
element laten fabriceren door KUKA-robot
4. Assembleren
elementen aan elkaar schakelen
Andrew Vande Moere
Corneel Cannaerts
Matthias Mattelaer
Hans Vanhove
Marc Lambaerts
Andrew Vande Moere
Corneel Cannaerts
Matthias Mattelaer
Test Cases

17. Planning
Januari Februari Maart April MeiNovember December
Case Study
In order to assess the applicability of the proposed panel system for large-s
further case study has been investigated by means of design and structural analy
case study is a shell spanning over four foundation points, which build a sq
8.15 m. The maximum height at the apex is 4.80 m.
Figure 8: Case study design for a large-scale freeform structu
The construction results in 100 panels with a constant effective thickness of 1
all panels, a die block with a height of only 650 mm is necessary. Due to the
geometry of the shell, 25 different typologies of panels are to be formed, and c
has to be adjusted 25 times to the panel shape by milling.
For the same symmetry reason it was possible to conduct static simulations w
model representing a fourth of the whole shell. A uniformly distributed live load
on the vertical projection of the shell surface has been assumed. With this simul
thickness of steel-sheets of standard steel grade S235 was dimensioned to 1.2
structure a maximum vertical displacement of 1.7 mm was observed in th
maximum tensile stress of 183 MPa. The overall weight of the structure results
average value of 24 kg/m2
.
In a first dimensioning the distribution of the stiffening cones over the su
maximum density possible with the fixed die configuration. The amount of co
25-27, depending on the panel geometry, whereas the total amount for the stru
Test Case 1 Test Case 2 Test Case 3
Eventueel verschillende (2 à 3) test cases, telkens op grotere schaal...
ure 5: Manufacturing steps for the structural layer of freeform panels: a) Milling of the
global die shape; b) Milling of the cones; c) Clamping the sheet; d) Stretch forming of
the global part shape; e) Incremental forming of the cones; f) Trimming of the panel
contour
panels have been formed from aluminum sheets of grade AA5182, with a thickness of
m. Certainly, the process is also transferable to other aluminum alloys as well as mild steel
en stainless steel grades, mainly depending on the dimensioning of the stretch forming units
machine in terms of applicable drag forces. An example of a produced panel is shown from
des in Fig. 6.
ure 6: Produced and joined freeform panel: Smooth outer layer (left); Structural layer (right)
entire assembled prototype structure is presented in Fig. 7 and serves as proof for the
ibility as well as the mountability of the panels.
ure 7: Assembled prototype structure with 8 panels (4 different panel shapes)

18. • structurele optimalisatie: evolutionair algorithme (Galapagos), topologische optimalisatie ?
• naast structuur, eventueel ook integreren van technieken: HVAC, verlichting,... ?
• context: gevelpanelen (VM Zinc?), dakconstructie (dakbedekking?),... ?
• toolpath in Grasshopper genereren
• SPIF zonder backing plate mogelijk?
• in twee fasen omvormen?
• niet loodrecht omvormen?
???

20. Unikabeton selected for Fabricate 2011 publication
http://www.digitalcrafting.dk/?p=1688
Topologische optimalisatie

21. cassette structuur
willekeurig rib-patroon
Eerste tests

22. Modeleren van structurele ribben