Ontwerp van een flexibele productie van inlegzolen
Sten Verhaegen
Promotoren: Jurgen Ceuppens, dhr. Marc Timmermans
Masterproef ingediend tot het behalen van de academische graad van
Master of Science in de industriële wetenschappen: industrieel ontwerpen
Vakgroep Industrieel Systeem- en Productontwerp
Voorzitter: prof. Kurt Stockman
Faculteit Ingenieurswetenschappen en Architectuur
Academiejaar 2013-2014
Masterproef Sten Verhaegen
Abstract
J. De Beukelaer nv - Débé is een producent van voornamelijk
vlakke inlegzolen. Ze produceren 3 types van inlegzolen:
kunststof, leder en licht gevormd. Daarbuiten produceren ze
nog een reeks van hulpstukken om het comfort van uw zool
te verhogen.
Door gebruik te maken van eenvoudige productietechnieken zoals kappen en lijmen gecombineerd met
handenarbeid verkrijgen ze een flexibel productieproces
waarin veel variatie mogelijk is.
Kunststof materiaal komt binnen als rollen gelamineerde stof volgens de gewenste samenstelling. Deze rollen worden vervolgens volautomatisch gekapt, uitgenomen en verpakt. De
lederen zolen worden handmatig gekapt omdat de fouten in het leer er uit gehaald moeten
worden. Nadien wordt er een onderlaag verlijmd. Als laatste kan er nog een voetbed of hulpstuk onderaan de lederen of kunststof zool toegevoegd worden om het comfort te verhogen.
Het doel van dit onderzoek is om de productie van Débé uit te breiden naar gevormde zolen.
Tijdens dit onderzoek is het belangrijk om te gaan kijken naar nieuwe materialen en technieken
die toegepast kunnen worden en daarbij de flexibiliteit van de productie te behouden. In samenspraak met Débé zijn er 3 types van gevormde zolen gekozen waarover het onderzoek zal gaan:
lichtgevormd model, model met veel details en een ondersteunend model.
J. De Beukelaer nv
2013-2014
Universiteit Gent
Iteratie 1
In de 1e fase werden er zonder al te veel voorkennis enkele concepten bedacht om zolen te kunnen vormen. Concept 1: Vacuümvormen
op een aanpasbare mal. Concept 2: PU spuiten in goedkope mallen afkomstig van een modulair mastermodel. Concept 3: Persen van een
thermoformeerbare schuimlaag met een aanpasbare stempel. Van deze concepten zijn enkele prototypes gebouwd die vervolgens zijn
afgetoetst aan de eisen en wensen van het project. Op deze manier kwam het stempelen in een schuimlaag als beste concept naar voor
Iteratie 2
Vooraleer het stempelconcept verder uitgewerkt wordt is het belangrijk om de gewenste resultaten duidelijk vast te leggen. Voor de
lichtgevormde zolen was dit redelijk eenvoudig: een gekromde rand rond de hiel met verhoogde zones ter hoogte van de hiel en de bal
van de voet. Bij het model met details komen hierbij nog eens vele kleine verhoogde zones kort op elkaar bij. Voor het ondersteunend
model werden de verschillende belangrijke zones gedefiniëerd en hoe deze wijzigen volgens de maten.
Aan de hand van deze analyse bleek dat de ondersteunende
boog niet van vorm veranderd en enkel van maat. Daardoor
kon er een mal ontworpen worden met een vast centraal
stuk en verwisselbare voor- en achterstukken
Het vaste centrale stuk werkte goed om de verschillende maten te produceren. Uit
testen met deze mal is gebleken dat een 2-zijdige mal noodzakelijk zou zijn en dat
een ondersteunend model enkel bestaande uit schuimmateriaal onvoldoende steun
zal kunnen bieden. De combinatie met een voetbed is noodzakelijk.
J. De Beukelaer nv
2013-2014
Om een geschikt materiaal te vinden om de zolen uit te
produceren ben ik zoek gegaan naar een schuim dat zich
makkelijk laat hervormen en goede eigenschappen bevat
voor in zolen (schockabsorptie,hardheid,...) Zo kwam ik
snel bij Polyethyleenfoams die al reeds gebruikt worden
in de sportindustrie als bescherming. Met enkele stalen
PE foam van Alveo heb ik de 1e testen kunnen uitvoeren.
Universiteit Gent
Iteratie 3
Tijdens de volgende stap in het ontwerpproces werden er 2-zijdige
mallen ontworpen van zowel het ondersteunende model als het
licht gevormde model. Deze mallen waren verder uitgewerkt om
getest te kunnen worden in het productieproces van Débé.
Met de nieuwe mallen werden niet enkel
de stalen PE foam van Alveo gestest maar
ook enkele nieuwe stalen die als basis
PE foam hebben maar gelamineerd zijn
met een onder- en/of bovenlaag. Beide
types van foams gaven goede resultaten
na kortstondig verwarmd en geperst te
worden.
Om de verhoogde zones ter hoogte van de hiel en de
bal van de voet en de details te testen zijn er enkele
kleinere teststukken ontworpen. De resultaten met
deze teststukken bewezen dat een modulaire mal
mogelijkheden biedt om de verhoogde zones te
wijzigen in maat of te elimineren. Ook bewezen ze
dat veel kleine details aanbrengen op een zool geen
probleem vormt met deze techniek.
Om het ondersteunend model af te werken werd
er een eigen voetbed ontworpen dat perfect in de
mallen past. Op deze manier kon aangetoond worden
dat de combinatie van een ondersteunend voetbed
met het vervormde PE schuim geen probleem vormt
wanneer men eigen mallen ontwerpt en CNC freest in
goedkope Polyurethaan schuimen.
Eindresultaat
Het eindresultaat is een productietechniek waarbij zonder al te veel wijzigingen in het huidig
productieproces Débé gevormde zolen kan gaan produceren. Gelamineerde rollen PE foam
worden gekapt zoals in het huidige proces. Deze gekapte vormen worden vervolgens kortstondig verwarmd en geperst in de mallen. Het opwarmen van het materiaal is nieuw maar de
persen hebben ze al staan. De mallen worden intern ontworpen en CNC gefreesd in goedkoop
hard PU om de kost te drukken. Door vanaf het begin deze mallen met de nodige intelligentie
te ontwerpen kan er veel flexibiliteit en modulariteit ontstaan.
J. De Beukelaer nv
2013-2014
Universiteit Gent
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Seriegrootte
Kost
Tijd
Afwerkingsgraad
Flexibiliteit in
eigenschappen en vorm
Maatbereik
Spuitgieten
Persmallen
Hoog
(massaproductie)
Hoge investering
Hoog
(massaproductie)
Hoge investering
Snel
Hoog
Nee
Snel
Hoog
Nee
Mal voor elke
maat
Mal voor elke
maat
Orthopedische
zolen
Laag (1 series)
Lage investering,
veel handwerk
Traag
Hoog
Ja
Elk stuk is uniek
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Gewicht (0-5)
Toelichting
Zool
Fysieke eigenschappen
4
Afwerkingsgraad
Combinatie van materialen
Proces
Past in huidig proces
Flexibiliteit in vorm
Flexibiliteit in maat
Kosten
Tijd
3
4
5
4
5
3
3
Schokabsorptie hiel, steun in brug,
energieoverdracht in bal
Afgewerkt product of nabewerking nodig
Kunnen alle materialen gecombineerd worden
# aanpassingen aan huidig proces
Vorm makkelijk aanpasbaar
Maat makkelijk aanpasbaar
Kost van investering en gebruikte materialen
Doorlooptijd van grondstof tot afgewerkt
product
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












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Licht gevormde zool
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Licht gevormde zool met details
Het laatste model verschilt niet veel van het
vorige. Dit model heeft ook een gevormde
rand rondom de hiel. Het grootste verschil
zijn de vele details op de zool. Zo zijn er niet
enkel verhoogde zones bij de hiel en de bal
van de voet maar de volledige zool bestaat
uit verschillende verhoogde zones.
Het doel van deze zool in het onderzoek is
om na te gaan of de vorming van deze
details mogelijk is met de nieuwe
technieken.
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
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Procesgrenzen
3
Kwaliteit van
de persing
2,5
0-1=Niet OK
1,5
Heating
1
Pressing
1-2= +/2-3=OK
2
Placement
0,5
0
10
20
30
40
50
60
Tijd (s)
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Flexible production of insoles – a case study
Sten Verhaegen
Jurgen Ceuppens
Student Industrial Design
Gent University
Kortrijk, Belgium
sten.verhaegen@ugent.be
Teacher & Researcher Industrial Design
Gent University - Industrial Design Center
Kortrijk, Belgium
jurgen.ceuppens@ugent.be
Abstract—This paper focuses on the development of a flexible
production process of insoles for J. De Beukelaer N.V., a
producer of flat soles. It describes the search to a low cost
manufacturing method, using new techniques and materials, with
possibilities in shape, size and kind altering.
Keywords—insole; flexibel production; low cost
I.
INTRODUCTION (Heading 1)
J. De Beukelaer N.V. is a small KMO which is active in the
insole industry. They produce mainly flat insoles. They feel
the need to expand their product range to shaped insoles,
going from simple aesthetic shapes to more functional
supporting shapes. Because they use very simple production
techniques and a lot of manual labor they have a very flexible
production process and can produce a wide range of products
with very little effort. This flexibility is the reason why they
still can compete against larger mass producers. It’s key for
the development of a new technique to produce these shaped
insoles in a flexible way.
II.
J. DE BEUKELAER N.V. - DÉBÉ
A. Types of insoles
Débé produces three kinds of soles: Leather, synthetic and
light shaped. The first two are completely flat soles were as the
third is lightly shaped yet not as much as a full orthopedic
insole.
The leather soles consist of a top layer of leather combined
with a bottom layer, accordingly to the wishes of the client.
Mostly the bottom layer is made of latex for anti-skid
properties.
The synthetic soles already have the desired combination of
top and bottom layers. They are produced by a company
specialized in laminating fabrics and synthetics into big sheets
of material. Those sheets are cut in the right size and shape by
Débé to produce synthetic insoles. The properties of the soles
can vary a lot from thermal protection, moist absorption to
Kevlar protection in safety shoes.
The light shaped soles are practically the same as the
leather and synthetic flat soles. The only difference is the extra
footbed that is added underneath the soles to give the sole its
shape.
B. Production method
There are three production methods used to produce the
insoles: Cutting, gluing and pressing.
The synthetic soles are cut from large sheets in the desired
shape and size using cutting dies. The production process can
be either fully automatic for large series or semi-automatic for
smaller series. After cutting the soles are ready for packaging
and shipping.
The leather soles are first cut from a sheet of leather into
the desired shape and size using a cutting die. Unlike the
cutting dies for the synthetic soles these cutting dies have to be
placed manually on the sheets of leather. This is necessary to
extract flaws in the sheets of leather. Then a bottom layer,
which has been cut in the same shape and size, is glued to the
leather sole by applying a layer of glue and pressure to the sole.
The leather sole is now ready for packaging and shipping.
The light shaped soles can be made of leather and synthetic
materials. They are made in the same way as the flat insoles
only a plastic footbed is glued and pressed to the bottom of the
insole. This gives the sole its desired shape.
C. Business structure
1. Internal structure
To obtain a better view of the internal structure of Débé
the different production processes and flows are analyzed.
There are 3 main parts in the business structure: The
management, the production leader and the production. Within
the production there are again 5 parts: Cutting, assembly,
stamping, packaging and shipping. All of these parts are
connected with each other as visualized in the diagram below.
The information flows mainly through the production
orders. Because it’s a small company there’s also a lot of
information passed by word of mouth. Production orders are
specific for every step in the production process.
These production orders go back and forth between the
production workers and the production leader. Any mistakes
or flaws are told by word of mouth. This way there’s no need
for the products to pass through the production leader and he
has a complete overview over the production.
The second type of flow is the material flow. When a new
production order is started, the production workers take empty
plastic containers from the stock en place the production
number on them. The products which are being produced are
placed inside the containers. When a step in the production
process is finished the containers go back to stock and the
production order is returned to the production leader. He then
hands out the next task in the production order to the same or
another production worker. By reading the production order
number the workers know which container they have to get
from the stock to proceed to the next production step.
III.
FLEXIBILITY
Fig. 1. Internal business structure
The owner and his administration, the management, are the
connection with the customers and suppliers and with the
production leader. The management prints out production
orders which contain information for every step in the
production process for every type of sole. These production
orders only get distributed to the production leader when the
stock is ready.
Before the production workers receive the production
orders they pass through the production leader. He is the
middleman between management and production. As the
former owner of the company he knows every production
process, material, time to produce,… and is very capable to
plan all the production orders. His job is to have at all times a
complete overview over the production.
The production itself consists out of 5 parts as seen in the
diagram. Insoles have to pass through all or some of these,
depending on the type of insole, 5 parts to be completed.
When a step in the production process is completed the
production order is returned to the production leader. When he
receives the final production order, the shipping order, he
knows the products are ready. He then returns the filled out
packing list to the administration. They now can check if all of
the products of this customer are ready for shipment.
2.
Information- and material flow
Between the different parts of the company there are flows
of information and flows of material (also flows of energy but
these will not be discussed in this paper). By dividing the
different flows we can see that the information, of products or
processes, doesn’t necessarily needs to be connected to the
materials.
A. Mass production vs mass customization
We can see an evolution of the manufacturing industry
through different paradigms since its birth two centuries ago.
First there was the “Craft paradigm” which creates products
specific to the customers needs but at high cost. Secondly
there was the “Mass production paradigm” which produces
products in high volumes at low cost but with low number of
varieties. The needs of customer are barely taken in
consideration during this paradigm. The latest change in
paradigm, due to global competition and consumer demands
for high product variety, is called the “Mass customization
paradigm”. During this paradigm manufacturers designed the
basic product architecture and options while customers could
chose the assembly combination they desire the most. Flexible
and reconfigurable production processes are needed to create
high variety in the final assembly stage. We now see a new
paradigm rising that shifts its focus from the shareholder value
to the customer value. This paradigm is called the “Mass
personalization paradigm” and has its foundations in cocreating and co-designing with the customers from the start.
This way customers have infinite amount of freedom to create
products specific to their needs [1].
Fig. 2. Volume variety relationship in manufacturing paradigms [2].
B. Product variety
More demanding customers and a global competition have
led to mass customization production processes. This
manufacturing technique has given customers personalized
products at the price of mass produced products. Mass
customization can be offered in two manners: product variety
and process variety. Product variety is defined as the diversity
of products that a production system provides to the
marketplace [3]. Process variety is the diversity and
complexity in the processes due to product variety and process
alternatives for each product variant [4].
Product variety shouldn’t be infinite. Too many options
can confront a customer with information overload, who uses
simple heuristics which often aren’t optimal. Fewer options
are therefore better but not at the expense of customer
satisfaction. [5].
Product variety addresses the pursuit of efficiency from a
product design perspective. By designing modular parts
customized products are created while minimizing costs,
delays, and internal complexity. [5].
C. Modularity
Modularity is key to produce a wide variety of products at
near mass production costs. Repetitive production of different
components who can be combined in a number of varieties is
the link between mass production and mass customization.
Flexible manufacturing systems (FMS) can lower the cost
of customization through the use of some sort of modularity in
their design.
Different types of modularity can be defined:
Fig. 3. Modularity types (Ulrich and Tung, 1991) [6]
D. Flexibility and modularity in Débé
Flexibility in production is Débés greatest advantage and
the reason why they still can compete with mass production
companies.
The reasons behind Débés flexibility are their very simple
production techniques which are cutting, gluing and pressing
combined with manual labor. All of the materials are imported
as sheet material and then cut in the desired shape and size
using cutting dies. The different layers can then be combined
to form different types of soles.
The modularity between different layers and their
combinations make it possible for Débé to produce a high
variety of products with little time, cost and effort.
E. Criteria for flexibility in the project
By analyzing the company’s current production process I
have set some criteria that will help me through the design
process. This way the process will remain flexible and it will
be the most suitable solution for Débé.

Combination of materials: Different kinds of materials
are combined to offer a high variety of products

Number of changes to current process: By lowering
the number of changes to the current production Débé
will be able to quickly adapt their process. This can’t
influence the quality of the solution.

Flexibility in size: Sizes 35 to 48 must be produced.

Flexibility in shape: This project must be applicable to
other shapes of insoles

Cost: The cost of the new method must be as low as
possible.
IV.
PROJECT
A. Shape analysis
Before a new technique could be developed it is import to
know which shapes need to be created. The production
technique should be applicable to a wide variety of shapes but
still it’s necessary to have a concrete shape to start with. In
concert with the company’s wishes and the demands we chose
3 types of insoles that are relevant for Débé at this moment:
(1) Light shaped insole, (2) insole with clear heel and base
marks and (3) a supporting insole.
1.
The second type of insole is not so different from the first
type. It also has a raised edge from the middle of the foot
around the heel. The main characteristics are the many details
on the center of the insole. They are a little bit thicker in
comparison to the rest of the insole so they add a little bit of
comfort but mainly they make the insole look better. These
details are the focus in the research to produce this kind of
insoles.
3.
Supporting insole
Light shaped insoles
Fig. 6. Supporting insole
Fig. 4. Light shaped insoles
The first type of insoles, and the main reason this project
was started, are the light shaped insoles. They fit a little bit
better in your shoes and around your feet but they just look
more complex and therefore better compared to the flat insoles
that Débé produces at this moment. For this reason they want
to expand their product range from flat insoles to light shaped
soles. The main characteristic is the raised edge from the
middle of the foot around the heel. At the heel and the
metatarsus there are slightly thicker areas for more comfort.
The location of these areas come from orthopedic studies but
in this case they have barely any orthopedic use.
2.
Insole with clear heel and base marks
The final type of insole is a supporting insole. They can
vary in shape and size and have a few similar properties such
as the raised edge and thicker zones at the heel and metatarsus.
Their main characteristic is their supporting qualities. A soft
material on top is combined with a rigid footbed on the
bottom. This combination gives the insole a comfortable
feeling while supporting the arc of the foot. Insoles like this
are the closest thing to orthopedic insole and are ideal for
people with minor complains about their feet, joints, …
everything that comes from a wrong stance. The focus with
these insoles is the combination of the footbed and a soft
material in one process.
B. Material analysis
Not only the shape of the insoles is import but also the
type of material it’s made of. The material has to meet certain
requirements in terms of manufacturability, comfort,
properties and look. Before searching a suitable material a list
of requirements was drawn up:

Deformable in the desired shape

Shock absorption for comfort

Starch enough to keep its shape

Breathable

Moist absorption
1.
Fig. 5. Insole with clear heel and base marks
Concept exploration
Before a type of material could be chosen, different
general concepts needed to be tested. This is necessary
because the material of the insole depends on the production
process. In this primary phase of the design process 3 concepts
were developed and tested.
The first concept is to form insoles through cheap molds
(silicone, plaster, …) via injection molding of Polyurethane
(PU). PU can be altered in many properties so the
requirements for insoles are met. To test this concept I casted
a silicone mold from an existing insole and inserted it with
liquid PU, combining the PU with a top and bottom leather
layer.
Fig. 7. Concept 1: Injection molding
For these main reasons, and a few other, I picked the foam
pressing concept for this case study.
2.
Material exploration
Now that the production technique is set I could start
searching for a fitting material that has the requirements for
insoles and could be formed by pressing. By searching
different types of foam materials and meeting with people in
this industry I quickly realized a thermo formable foam would
be best to use in this concept. After some first tests with
memory foam and Thermoplastic Polyurethane (TPU) I came
across Closed cell cross-linked Polyethylene (PE) foams. This
thermo formable foam is already widely used in the sport and
leisure industry and has excellent shock absorbing properties.
PE can be altered with different additives to make it softer,
more flexible,… [7]. The foam material can be laminated with
different top and bottom layers to meet the breathable and
moist absorbing requirements.
The second concept is to press a foam layer into the
desired shape. The shape is created by using a molded surface
and pressing it onto the foam. By combining different top and
bottom layers before the forming of the insole the different
layers can be cut in the traditional way.
Fig. 10. Azote foams, sport and leisure applications [7]
I received a series of PE samples with minor differences in
properties. After heating and pressing these samples in a mold
some very good first results came out.
Fig. 8. Concept 2: Foam pressing
The third and final concept is to vacuum form a
thermoplastic plastic into the desired shape using a 1-sided
mold. Again by combining different top and bottom layers
before the forming of the insole the different layers can be cut
in the traditional way.
Fig. 9. Concept 3: Vacuum forming
After comparing the 3 concepts the foam pressing concept
gave the best results. It doesn’t need complex injection molds
or any type of extruder to mix and insert the materials as the
first concept. Foam also gives the best comfort and can easily
be formed in comparison to the plastic from the last concept.
Fig. 11. Samples PE foam
After testing the PE foam material I recieved a few
samples with different top and bottom layers but all with a
core of PE foam. When heated and pressed these samples gave
the same good results as the PE foam alone.
Fig. 12. Samples laminated PE foam
Because the material is shipped as laminated rolls it fits
perfectly in the current production process of Débé. By
altering the top and bottom layers they could produce a wide
variety of shaped insoles with the same technique.
C. Molding exploration
To give the material the desired shape some sort of mold is
necessary. From the beginning until the end of the project
different types of mold are prototyped to test the forming of
the insoles.
1.
After testing with the first milled molds in low density PU
it came to light that a 2-sided mold would be necessary to
produce the desired shapes of insoles.
Molds exploration
At very early stages in the design process molds made from
PU foam and coated with putty were used to test the forming
of the material.
Fig. 16. High density PU mold
2.
Advantages of CNC-milling
By designing the molds, in CAD programs, with flexibility
and modularity in mind, CNC-milling provides all the
necessary tooling to create pressing molds. Combining these
possibilities with internal CNC-milling, even at prototyping
scale, very fast and very good prototypes can be tested and
shown to customers.
Fig. 13. Foam and putty mold
Secondly I started exploring with the possibilities to divide
molds and thus creating 1 centerpiece for all the sizes and
different add-ons to alter the size and type of insole.
Some details and modular parts were created and tested to
show the possibilities with CNC-milling.
Fig. 17. Detail testing molds
Fig. 14. Plaster mold
The first 2 types of molds were handmade or casted from
existing insoles. Because future molds in the production
process won’t always have a parent model and will have to
have a certain precision I started exploring with rapid
prototyping possibilities.
Fig. 18. Detail testing results
Molds could be created to combine plastic footbeds with PE
foam. This way supporting insoles can be created using the
same production technique
Fig. 19. Footbed testing mold
Fig. 15. Low density PU mold
CNC-milling and 3D-printing, both flexible manufacturing
techniques, would be able to produce molds that could be used
to press insoles. The advantages of 3D-printing, undercuts and
complex shapes, aren’t fully used in these molds, the range of
materials is smaller and it’s more expensive. Therefore CNCmilling has been chosen as the production method of the
pressing molds.
A final test with CNC-milling is the creation of
exchangeable parts to make a centerpiece with different addons to save material for different sizes and types.
Fig. 20. Exchangeable parts in molds
D. Implementation in the current process
Tests with CNC-milled molds and laminated samples gave
some very good results which is proof the technique works.
Not only the technique is important in the project but also how
this technique will work in the current production process.
During the design process the current production process was
kept in mind to minimize changes and costs.
1.
Fig. 24. Separating line
2.
Cutting
The laminated PE foams are distributed as rolls, because
Débé already has the infrastructure to cut roll materials using
cutting dies a small test was set up. I cut a small piece of PE
foam with the press and cutting die they use and there was no
problem.
Heating
When the insoles are cut they have to be heated to become
formable. The cheapest and easiest way to do this is with a
convection oven. In this project I choose for a conveyor belt
oven because it has many advantages: The temperature can be
set, the speed of the conveyor belt can be set and the material
can’t be heated too long. This is all necessary because
different types of laminates may need different temperatures
of heating times.
Fig. 21. Die cutting test
When the soles are cut in the desired shape they have to be
placed in the molds by the production workers. By cutting the
soles in pairs and keeping them together every pair comes
from the same roll and from same position on that roll. This
maintains the quality if the insoles. To choose a cutting pattern
which has the best handling some different types were tested
with the production workers
Fig. 25. Conveyor belt oven
3.
Pressing
Heated pairs of insoles come out of the conveyor belt oven
and can be placed inside the mold. Positioning holes in the
cutting pattern make sure the soles are always on the right
position. When the insole is placed the press can be closed and
the material takes it shape while cooling down. Also here
some adjustments can be made to the pressure of the press
depending on the type of laminate.
Fig. 22. Cutting patterns
Fig. 26. Press and closed mold
4.
Process boundaries
PE foams (laminated or not) need a certain temperature to
become thermo formable. Therefore I searched the boundaries
of the material using a small oven set to 200 °C. With this test
I could determine the minimum time for heating, the
maximum time for placement and the minimum time for
pressing/cooling.
Fig. 23. Chosen cutting pattern
After cutting and shaping of the insoles they have to be
separated from each other before they can be packed and
shipped. Different cutting patterns were tested to see which
one was the easiest to be separated by hand.
have to use by the number on the order. The oven is preheated and the forming can begin. When an insole is pressed
they are placed again in boxes with the same production
numbers.
Fig. 27. Process boundaries test
The final stage in the production process is packaging of the
insoles. Again the production number tells the workers which
boxes are needed. The insoles in the boxes are still contected
with each other but the cutting pattern makes it easy to
separate the pairs. When the insoles are split the leftover
connecting piece is discarded en the insoles are put in their
packaging.
The production flow doesn’t change a lot, the use of
production orders is kept and every step can be executed on its
own. The main change is the introduction of CAD drawings
and CNC-milling before the production and during the
production the task of forming the insoles through heating and
pressing.
Fig. 28. Process boundaries schedule
The data collected from the boundaries tests tells us the
minimum time for heating is 40-50 seconds, the maximum
time for placement is 20-30 seconds and the minimum time
for pressing is 30-40 seconds. The test was executed with 1
form of PE foam therefore the results are given as a time span
because the heating, placement and pressing times can change
with the material types. These values give us an idea how long
the process will take to produce 1 pair of insoles.
5.
Production flow
Starting from the analysis from the current production
process I have been able to fit in the new technique with as
few changes as possible.
To begin Débé will have to introduce CAD drawings and
CNC-milling into their company. The person who operates
these programs and machines is from the highest importance
because it’s only by smart designing the molds flexibility and
modularity is created. This person will be in contact with the
management, and maybe directly with the customers, to
specify the shapes and needs off the molds. He will also make
the first prototypes and test them with the production workers
and consult with the production leader. When a mold is ready
Débé has to decide if they want to produce their own molds or
outsource this cost.
When the molds are ready material can be ordered. Nothing
changes here, an order is placed and the material is delivered
as rolls. Now the production leader hands out the cutting order
with all the information (cutting die, size, amount, time, …)
needed to the worker. After cutting the pairs of insoles are
stored in boxes with a production number on them.
Pressing orders are handed out when the cut insoles have to
be formed. The production worker knows which boxes they
Fig. 29. Internal structure with new techniques
V.
CONCLUSION
By introducing CAD software and CNC-milling in the
production process every kind of shape of insole can be
produced thus creating complete freedom. Because every
insole is different a thorough analysis of the shape is necessary
to design the molds as smart as possible. This way modular
parts can be added or removed to create new insoles or shapes
with the same mold. This combined with cheap PU materials
creates flexible molds at a low cost.
PE materials which can be thermoformed are imported as
rolls and can be processed in the same way as the current
process. Adding two steps in the process, heating and
pressing, are the only changes in the production process.
Every process can be executed on its own not depending on
the previous processes. This way flexibility is kept.
VI.
[1]
[2]
[3]
[4]
[5]
[6]
[7]
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