A Customer's View on Key Aspects of Metal Additive Manufacturing.
Nozar, Martin ; Zetkova, Ivana ; Hanzl, Pavel 等
A Customer's View on Key Aspects of Metal Additive Manufacturing.
1. Introduction
1.1. Additive manufacturing
Additive manufacturing (AM), also known as 3D printing, rapid
manufacturing, additive fabrication, additive processes, additive
techniques, additive layer manufacturing, layer manufacturing, and
freeform fabrication is defined by the American Society for Testing and
Materials (ASTM) [10] as "The process of joining materials to make
objects from 3D model data, usually layer upon layer, as opposed to
subtractive manufacturing methodologies".
These technologies have witnessed intensive development in recent
years and have found their applications not only in industrial and
prototype manufacturing. Nonetheless, they are very specific and their
production potential significantly differs from conventional production
technologies. Although they can create very complicated shapes and
structures which were previously almost impossible to manufacture, these
technologies have their own limitations and are not capable of doing
everything that a designer could invent. Specialists working with this
technology are well aware of its capabilities and limitations, but for
customers it could be quite difficult to properly consider its
capabilities with respect to the required parameters and to correctly
formulate their requirements. Because of this, they are often dependent
on recommendations from specialists, who have to identify and formalize
all the relevant data. However, in order to take complete advantage of
the opportunities offered by the technology, it is necessary to know
exactly what is manufacturable using this technology and what is not.
For this purpose, this article tries to take a closer look at the
options offered by additive manufacturing from a customer's point
of view and to study the printing of one specific component, with
emphasis on three important factors--price, quality and delivery date.
Its motivation is to point out, with the help of a simple experiment,
the differences from conventional manufacturing that may not be obvious
but which could have a significant impact on the properties of the final
product, and to answer questions that customers may have when
considering the manufacture of a particular component using this
technology. The experiment, in which several test prints and print
simulations are carried out, clearly illustrates the differences in
price, time and quality of identical components printed in different
ways and in different sizes and quantities. In doing so, the key aspects
of this technology are demonstrated here, and the question is answered
whether higher quality always means higher costs in the additive
production process, and to what extent cost-saving efforts could
negatively affect the quality of the manufactured component.
1.2. Advantages, limitations and key aspects of additive
technologies
Additive technologies in themselves have a number of advantages
over conventional manufacturing methods. Among the most prominent is the
possibility to design parts with unlimited complexity, allowing twisted
and contorted shapes, variable wall thickness, blind holes and screws,
and very high strength-to-weight ratio. And therefore, since the
manufacturing of complex aesthetic shapes is no longer a problem,
designers can focus on designing exceptional part functionality and
assembly--additive technology allows several parts to be combined into
an integrated assembly. [4] Moreover, additive technologies allow the
true customization of every product--every single part, built at the
same time, can have a different shape or size. And in doing so, there is
no need for tooling development, so additive technologies make the
production process faster by passing from design to production.
On the other hand, there are some drawbacks associated with these
processes including high machine, material, and maintenance costs, slow
production rate, limited build sizes, dimensional accuracy, and the
small variety of materials available for processing. In comparison to
conventional manufacturing, there are some unexpected downsides, which
are generally based on a particular AM machine (i.e. its building method
and parameters), and particular settings of the building process. A
specific product's design, considering possible build problems and
constraints, needs to be carefully analysed in order to achieve such
optimal parameters for the production process [12].
In terms of quality, the most important aspects of a final product
are its mechanical properties, dimensional and shape accuracy, and
surface roughness. All of these aspects can be influenced by the correct
setting of the processing parameters (for more details see e.g. [7]),
above all with:
* Laser power and scanning speed on the structure of the material
* Hatch angle (the angle between laser scanning directions on
individual layers)
* Building orientation (the acute angle between the longitudinal
axis of a fabricated part and the vertical axis)
* Layer thickness
* Overlap rate (the amount of area which is influenced by repeated
sintering with the energy beam)
While there is often no ideal combination of these parameters, it
is always necessary to consider the following negative factors which
decrease the quality of the final component:
* Staircase effect (a negative effect causing surface roughness to
increase and degradation of dimensional accuracy due to orientation of
the printed part on the platform)
* Volume shrinkage (risk of degradation of shape and dimensional
accuracy caused by print settings)
* Heat dissipation (risk of possible deformation of printed parts
due to laser heat transfer to surrounding material)
* Removability of support structures (hard to remove or impossible
to remove supports, particularly of internal structures and cavities)
* Tension in material (presence of temperature gradient along the
Z-axis of the part bed, which must be removed by subsequent heat
treatment)
To a certain extent it is possible to influence all of these
factors by suitable settings of the process parameters, but in the
described experiment the setting of the layer thickness, the printed
component orientation and creation of effective support structures are
crucial (while maintaining the other parameters of the recommended
settings). While the layer thickness could be set up as needed
(according to the machine parameters), the support structures depend on
the chosen orientation. However, the decision on a component's
orientation has much more significant consequences. In addition to a
component's mechanical properties (anisotropy), it influences the
surface quality, processing time and costs. These aspects, which are
particularly important and examined in this article, are influenced by
the component orientation as follows [2]:
* The height of the part in the build direction, which is directly
related to the total build time and hence final cost
* Total volume of support material used. The support structure does
not contribute towards the finished part, wasting both build time and
material
* Total area of contact of the part with the support structure.
Reducing contact area decreases the time and the cost of removing
supports and finishing surfaces
* The quality of selected faces (or total surface area) measured by
surface accuracy. How a part is oriented determines which faces are
subjected to the staircase effect and which are in contact with
supports. Both these factors deteriorate the surface quality of the
manufactured part
2. Specifications and parameters of the experiment
2.1. Building technology
The experiment described in this article was carried out using
Direct Metal Laser Sintering (DMLS) technology. This technology is one
of the major additive methods used to manufacture metal components. In a
nutshell, this method operates as follows: A 3D model in "stl"
format is redesigned as required (above all, any surface errors and
inappropriate shapes are eliminated), support structures are generated,
road paths are calculated and then the model is digitally cut into
discrete slices. These slices are sent to the DMLS machine, which
recombines them in a layer-by-layer sequence. The machine selectively
scans the surface of the metal powder bed with a fibre laser,
effectively creating a thin, planar slice of solid part geometry. Once
the sintering of the layer is complete, a new specific increment of
metal powder is deposited and the sintering of the next layer commences.
This cycle is repeated until the build is complete [2].
2.2. AM machine technical data
An AM machine of type EOS M 290 was used for this experiment. This
model has a building volume 250 x 250 x 325 mm and uses a Yb fibre laser
with 400 W beam power, up to 7.0 m/s scanning speed and 100 pm focus
diameter. EOS Maraging Steel MSI (AKA 1.2709 or X3NiCoMoTi 18-9-5) with
8.0 g/cm3 density was used as build material, and Argon was used as the
protective atmosphere.
2.3. Model component
The model part selected for printing can be seen in Figure 1. This
component in various orientations and quantities was used for several
trial prints and simulations. The orientation of the component on the
platform has a significant effect on building time, quality and the cost
of the final part. The aim of the experiment is to compare 4
orientations to find the lowest cost, processing time and the best
quality of the component.
For the comparison, the component was printed in 3 variants with 20
and 40 pm layers and in different orientations (see Fig. 3) which have
specific advantages and disadvantages. The basic variant was a printing
simulation of a single component on the platform. The next, in order to
take into account the effect of the size on detected values, was the
simulated component print in the given orientations but with four times
larger dimensions. And the last, due to the obvious high cost of
printing single components, represented a print simulation of the
maximum possible number of components on the platform (Fig. 4).
3. Qualitative aspects
3.1. Build orientation and support structures
Building orientation is a very important factor that affects the
build process as well as the post-processing costs and mechanical
properties. For instance, it causes anisotropy of the tensile properties
of every fabricated part and therefore the placement and angle of
rotation on the platform have to be chosen optimally according to the
functionality of the part. Special attention must be paid to the fact
that this direction also predetermines the number and volume of the
support structures required.
The model component was printed in positions as shown in Fig. 6--9.
The supports are shown in red. The volume of these components and their
supports are given in Table 2. The supports were automatically generated
by Materialize Magics software and adjusted as necessary.
The positons in Fig. 6.-9. were chosen intentionally, above all
with respect to the following principles of building orientation and
support creation [2]:
* Minimizing the part's height (consistent with Orientation
No. 1)
* Maximizing the stability of the object by selecting the largest
base convex hull (consistent with Orientation No. 1)
* Minimizing the volume of the support to reduce excess time and
cost of depositing and removing wasted material (consistent with
orientation No. 3)
* Minimizing total surface area of contact with the support to
reduce support removal and finishing time (consistent with orientation
No. 3 and partly No. 4)
* Maximizing the surface accuracy of the part for better part
quality, which will reduce the finishing time (consistent with
orientation No. 2).
3.2. Quality evaluation of individual components
As already mentioned, using the appropriate build orientation and
support structures can significantly improve the quality of the part,
because a major source of part inaccuracy and degraded surface
properties are contacts with support structures and the staircase
effect.
Therefore, it is wise to minimize these factors as much as possible
to avoid post-processing (grinding, polishing, etc.) operations.
Unfortunately, meeting these requirements can be quite complicated
because on the one hand functional areas should be oriented either
horizontally or vertically to maximize surface accuracy, and on the
other hand horizontal downfacing surfaces need to be supported, while
vertical ones do not. This is exactly the main problem of orientations
No. 3 and 4 in our experiment.
In the experiment, the parts were printed in 40 [micro]m and 20
[micro]m thin layers. As expected, the thinner layers were always of
higher quality, but the printing time was roughly double, as can be seen
from Table 1. A partial solution to this could be the option of setting
individual layers, which enables different parameters to be used locally
and depositing thinner layers only where necessary. Modern AM machines
already have this functionality, which can improve surface properties,
without increasing costs too much. In the case of the EOS M 290 printer,
this is enabled by the latest EOS Print 2.0 software [9].
Orientation No. 1: This orientation is not very recommendable due
to the great volume of the supports. These supports negatively affect
the quality by contacting the printed components across a too large
surface, even in the internal parts, from which it is relatively hard to
remove them. Thus, the printed component will still have to be machined.
Orientation No. 2: This orientation shows a relatively small volume
of supports, but unfortunately, some of them are internal. The main
advantage of this orientation is the shape and dimensional accuracy.
However, some internal and functional areas in the lower part of the
component need to be machined.
Orientation No. 3: This orientation has the minimum volume of
supports, which is achieved by rotation of the component, meaning that
there is no need for internal supports (except for two tiny and easily
removable internal supports). The main disadvantage is the degraded
surface quality due to the staircase effect. For a component printed in
this way, it is suitable to create it in 20 [micro]m layers or use some
subsequent finishing operations.
Orientation No. 4: The component with this orientation has
relatively extensive supports, but only external ones (except for one
tiny and easily removable internal support), and provides the printed
component with good stability and heat dissipation. Due to the large
contact of the supports with the body of the component, subsequent
finishing operations are required, as in Orientation No. 3.
4. Time aspects
4.1. Processing times
Many relevant studies [1],[3],[6] in accordance with observations
from practice confirm that the manufacturing time per part is the key
factor to optimizing the costs of additive manufacturing. The time spent
on the whole building process consists of:
* Pre-processing time (model preparation, machine set-up, machine
atmosphere generation, machine warm-up, etc.)
* Processing time (scanning time, Z-axis movement, levelling,
non-manufacturing movement of the nozzle/laser, etc.)
* Post-processing time (cooling time, machine cleaning, unused
powder sifting, sawing pieces from the platform, finishing operations
such as heat treatment, milling, polishing, etc.)
In our experiment, we took into account only the processing time,
since pre-processing times are practically the same for all positions,
and the post-processing times differ primarily in the finishing
operations required by a customer or by the function of the printed
component. Generally, post-processing times can be reduced in various
ways that are, however, different for each and every component, and
therefore they have not been taken into consideration, neither have we
considered time losses caused by possible failures or repairs of
defective components.
A simulated print was performed to compare the print times of model
components in different orientations--the prepared models were sent to
the machine, which determined the exact printing times. The simulated
print was made for variants with single component printing, enlarged
component printing, and print of multiple components with original size.
In this variant, the building platform was completely filled with
components so the part in Orientation No. 1 was printed 20 times, 55
times in Orientation No. 2, and 48 times in Orientations No. 3 and 4.
See Fig. 6.-9.
Processing times of the model component in the different
orientations and variants are given in Table 1.
4.2 Evaluation of component processing times
As shown in Table 1., the fastest possible print of the component
can be achieved in Orientation No. 1. when applying 40 pm thin layers.
In contrast, when applying 20 pm thin layers in Orientation No. 2, the
print is almost four times longer, due to the largest building size of
the component in this orientation. This is also the reason why the time
values for orientations No. 3 and 4 are quite similar, since the
components have the same building height. Observable differences are
only caused by the difference in support print times, and these are more
massive in Orientation No. 4.
In general, printing using 20 pm thin layers is roughly two times
longer than for 40 pm layers. A big difference is evident between the
time of printing the original and the enlarged component, which is 4
times higher, but the print time is 6-10 times longer. This
disproportion is caused not only by the printing of a greater volume,
but above all by the significant building height, which means many more
deposited layers, and hence more time spent on the recoating procedures.
5. Price aspects
5.1. Costing estimation for additive manufacturing
There are several approaches to determining the cost model of
component production using AM. It is possible to use the model below as
an example [1]. The highlighted costs are important for the following
calculations and the printing cost evaluations.
5.2. Structure of the processing costs
It is possible to find these with economic (or cost) models (e.g.
the model above) and the prices of particular components in various
publications (e.g. [1],[5]). However, this article is not concerned with
determining the total cost or price of printing, just costs that are
directly related to the printing of the model components in the given
orientations. For the purpose of costs quantification real and current
prices were used, which are not stated in detail in this article,
because these calculated costs, no matter how thoroughly they were
identified, have only relative informative value and they are stated
here just for the possibility of making different options and comparing
orientations.
It is not possible to compare these costs with the cost of
manufacturing using a different AM machine as material prices depend on
the time when the calculation was made, on the country where the survey
is conducted and the current exchange rate (this calculation was made
with prices valid in the Czech Republic in September 2017 and in Czech
crowns). Further differences in the calculation may be caused by the
selected (or required) material, which may have different processing
properties and parameters.
Using a different printer could also cause significant differences,
as it may have different production capabilities. For example, a printer
could have a significantly larger workspace (i.e. multiple components
can be printed concurrently), it could be a hybrid AM machine (i.e.
capable of machining printed shapes during a printing process) or a
multi-laser machine (usually using 4 lasers to shorten the processing
time), or a printer could be equipped with a sieving module (to shorten
times of powder recycling and to reduce powder material losses).
However, all these benefits mean increased investment costs for the
acquisition of the AM machine and its appropriate equipment.
Very significant differences in values can also be obtained if we
take into consideration the operator's capabilities and the
equipment's operating conditions, in particular the service
lifetime and worktime fund of a given AM machine. In the case of the AM
machine used in this article, its user is a university research centre,
which uses this AM machine for research and prototype development. This
means a larger portion of pre-processing time, shorter working hours and
potentially longer service lifetime than printers used for commercial
production. All this is reflected in the hourly machine rate, which is
based on the purchase price and the depreciation method of the AM
machine. That is why there are almost no absolute sums here, as they
virtually would not be predictive.
To complement this topic, we recommend an article [1] in which the
authors made a cost calculation based on 60% utilization of the machine
time fund in 8 years, i.e. at the limit recommended by the machine
manufacturer. A study [8] from 2016 is also very interesting and
relevant, in which its author compared three different AM systems
(including the EOS M 290) and stated the hourly machine rates with
proportions of their individual components. Considering a 5-year
depreciation period, utilization 5 000 h p.a., 10% maintenance and
downtime, the hourly machine rates (include only processing time, i.e.
without material and direct labour costs), range from 35--45 EUR/h for a
'small single-laser' machine to 90-120 EUR/h for a 'large
machine'.
5.3 Relevant costs calculation
Calculated costs considered in our experiment include material
costs (energy and gas) and processing costs (which result from
processing time, so they include machine depreciation and regular
maintenance costs). The consumption of metal powder is calculated
according to the volumes of the printed components and their respective
support structures. Both these volumes are stated in Table 2.
It is necessary to add the volumes of metal power depreciated and
lost during processing and post-processing operations and which cannot
be reused, to the volumes stated in Table 2.. According to the producer,
2- 4 % of the powder material is considered waste.
However, according to our own measurements (accurate material
weighing before and after printing), EOS MS1 metal powder losses reach
up to 25% of the printed component's volume. Therefore, this amount
of metal powder was added into the calculated consumption. The
consumption of electric power (above all of the printer and compressor)
and gas (e.g. Argon; to create a protective atmosphere) was also put
into the calculation.
This calculation revealed (in accordance with some previous studies
[1],[4]), the major part of the cost is found to be due to investment in
the machine and regular maintenance costs. The costs of energy and
materials only contribute to a small extent. The sum of costs
([C.sub.[SIGMA]]) and share of processing cost ([C.sub.pt]) for all
simulated orientations and variants are shown in Table 3. The sums of
costs are stated in Euros (recalculated with current exchange rate 26
EUR/CZE). Note: Qmax is the maximum number of components on the
platform.
5.4. Evaluation of variants
As outlined in Table 3., when printing single components, the
cheapest component is printed in Orientation No. 1, with no difference
when printing in 20 or 40 [micro]m thin layers. In other cases, the
cheapest printing is in orientation No. 3, with the exception of
printing with a maximum number of components in 40 [micro]m thin layers,
where costs are even slightly lower. The values given above also
indicate how beneficial the horizontal filling of an AM machine working
space is. The greatest savings are thus obtained when printing in 20
[micro]m thin layers (on average 78%), especially in orientations No.2
(84%) and No.3 (85%). As expected, printing in 20 [micro]m layers is
always more expensive; for single component print variants on average
twice as expensive, for multiple component print variants 1.5 times as
expensive, and for large print variants 1.7 times as expensive.
This table also shows that the decisive factor in the calculated
costs is the processing cost (in another words machine investment cost),
which reaches on average 94% (for all orientations and both layer
thicknesses) during single component printing. This value does not fall
below 80% on average, even in the cost calculation of the multiple
component print when the total cost is distributed per piece, or in the
cost calculation of the enlarged component print. Even when considering
the maximum recommended machine utilization, as used in the article [4],
the average percentages of processing costs do not fall below 88% in
single print variants and below 64% in large and multiple print
variants. In this case, the total lowest values were reached by printing
on a full platform with components in orientations No. 1 and No. 2.
However, the percentage values exceed 52% here as well. Therefore, it is
clear that there is no print variant where the processing costs would
not be the decisive part of print costs.
As a result, it is possible to state that in terms of price, the
volume of the support structures is not a decisive factor (unless such
support structures require complicated and costly removal), and filling
the available AM machine build space is the prime determinant for the
efficient operation of the technology.
6. Evaluation of experiment results
The purpose of the experiment was to evaluate the printing of a
model component in various orientations and three different variants
which were simulated by AM machine. The evaluation was carried out with
regard to quality, processing time and cost. At the end, the component
was printed in order to confirm all our conclusions.
As it turned out during the evaluation, it is not possible to find
an ideal component orientation when taking into account the aspect of
quality--each orientation has its own advantages and disadvantages, and
it is a matter of individual assessment to determine which of these
factors are less problematic for the customer and the function of the
printed component. A qualitative aspect is therefore useful purely as a
guide. A quite similar case is also the time aspect where the component
orientation is not decisive, unlike the size of the printed volume.
However, processing time is a determining factor for processing costs,
which, as has been shown, creates the main part of the printing costs.
In terms of time, orientation No. 1, which has the smallest
building height and therefore the smallest number of printed layers,
would be the ideal case. Unfortunately, this variant is not the most
cost-effective option (it is most cost- effective only when printing a
single component, which is the least economical variant) and, moreover,
a high volume of internal and external support structures require a
large number of finishing operations which increase production time and
costs. The disadvantage of this orientation is also the fact that when
printing more components at the same time, this component can be placed
in the smallest quantity (20 copies) on the building platform.
Therefore, when printing a large number of components in this
orientation, this printing option ceases to be favourable in both cost
and time.
As expected, it reveals the key aspect to be the price, implicitly
including the time aspect. Thus, if we prefer the price aspect, it seems
orientation No. 3 is the most favourable one in most cases. However, in
this case it is necessary to take into account the deteriorated surface
quality due to the staircase effect. This can be partially avoided by
printing this component in 20 pm thin layers, which means an increase in
costs of 40%.
In this context, it is necessary to draw attention to the possible
instability of this component during printing due to the small number of
support structures that could cause printing defects. Because of this
risk the component in orientation No. 4 is equipped with more massive
support structures.
These support structures increase the processing costs on average
by 16%, but provide the printed component with greater stability and
better heat transfer from the laser beam into the surrounding material.
However, a component oriented in this way is also liable to suffer a
deterioration in surface quality due to the staircase effect.
This undesirable effect has almost no impact on the component in
orientation No. 2, which is oriented perpendicularly to the building
platform, and thus attains the highest quality in shape and size. A
component printed in this orientation is one of the most expensive ones
in most cases, but it is possible to print it in the largest number of
copies (55 copies) concurrently, but when printing even with a full
building platform, the price per component exceeds even the cheapest
orientation No. 3. In contrast to this orientation, it has the advantage
of having a good surface even when printed in 40 pm thin layers, but the
disadvantage is that there are internal support structures at the bottom
of the component, which need to be removed.
When considering time and cost, it is quite easy to identify the
optimum orientation in given circumstances. unfortunately, in the case
of quality the situation is much more complicated because each
orientation has its pros and cons. And insufficient quality could mean
repeated printing, which doubles its original price. Therefore, for
practical printing it is advisable (due to the significant disparity
between material and processing costs) to print the component with a
more massive but safer support structure (unless it could cause
complications during its removal), to carry out a test print, e.g. add
this component to a different print batch in order to verify its
properties, or to print this component in several efficient orientations
concurrently. There are several approaches to manufacturing a suitable
component, but when seeking the best one it is always necessary to know
whether quality (i.e. functional properties), time or costs matter the
most.
7. Conclusion
This article is dedicated to metal additive manufacturing, which
uses a laser beam to melt metal powder to form solid objects. Basic
aspects of this technology are presented, its capabilities and
limitations that need to be taken into account when considering
manufacturing using laser sintering. The article explains that it is not
enough just to solve whether the required piece or component can be
printed at all, but also the importance of the orientation of this
component during printing. From the customer's point of view it is
essential to what extent just this orientation directly affects the
quality (surface and mechanical properties), processing time and
processing cost. Therefore, this article attempts to give answers to the
basic questions regarding which factors affect price, quality and
processing time; how to save costs without compromising quality; and
whether higher cost and longer processing time always result in better
quality. At present, there is some software capable of optimising the
arrangement and orientation of parts on the platform, but it only
provides recommendations made with regard to appropriate criteria. But
as demonstrated in the article, as a rule, every single orientation has
its positive and negative aspects, so the final decision about the build
orientation is always up to the specialist/customer who has to
thoroughly assess the specific situation.
For the purpose of comparison of different building orientations on
the platform, i.e. above all for finding the connection between quality,
costs and building time, we prepared different printing models, created
a calculation formula, quantified cost components and simulated printing
of these models. The values we obtained enabled us to compare and
evaluate all the orientations and variants from the customer's
perspective.
The experiment was carried out on an EOS M 290 machine and based on
printing a selected component in four different orientations, quantities
and sizes; and the values obtained from each of the simulations were
recorded into 3 tables for cross-referencing. As it turned out, when the
results were evaluated with regards to quality, time and cost, every
orientation and print variant has its own specific advantages and
complications, so when deciding on individual print adjustments (not
just the number and orientation of components), the key question is
always whether to prefer quality (i.e. properties), time or price of
these components. Sometimes the solution is unambiguous, but in a number
of cases it is, unfortunately, a matter of compromise. However, since
the processing time is the largest price factor, all measures to reduce
the time also reduce the cost accordingly. As a result, additive
technology users should fill the available build space with as many
parts as possible because the manufacturing time per part is the key
factor to optimizing the costs of additive manufacturing.
This article describes the issue from the perspective of the
customer, who is primarily interested in quality, costs and printing
time of the required component. However, this issue is more complicated
and subsequent research will be conducted in two principal directions.
On the one hand, the complete cost formula will be specified (i.e. all
parts of the cost model on Fig. 10 will be considered) and a precise
formula for building time calculation will be created (all the time
values stated in this article were individually indicated by the
machine). These formulas will enable us to create a special computer
programme able to calculate and recommend optimum placements and
building orientations of every piece by using advanced simulations and
genetic algorithms. The orientations considered in this article are
intentionally chosen to point out the differences between these de facto
extremely different building directions, however, it is probable that
the best option in many cases would be a combination of these
orientations. Although it is possible to use a computer simulation to
find such a combination, it requires a clearly and precisely determined
criterion function, i.e. exact values of key parameters and their
connections with processing parameters. Therefore, parallel research
will investigate the impact of all the processing parameters on costs,
quality and building time.
DOI: 10.2507/28th.daaam.proceedings.133
8. Acknowledgments
The article has been prepared under project LO1502
'Development of the Regional Technological Institute' under
the auspices of the National Sustainability Programme I of the Ministry
of Education of the Czech Republic aimed at supporting research,
experimental development and innovation.
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International, ISBN 978-3-902734-07-5, ISSN 1726-9679, Vienna, Austria
DOI:10.2507/26th.daaam.proceedings.037
Martin Nozar, Ivana Zetkova, Pavel Hanzl & Milan Dana
Regional Technological Institute, University of West
Bohemia--Faculty of Mechanical Engineering, Univerzitni 8, 306 14
Pilsen, Czech Republic
Caption: Fig. 1. Model component
Caption: Fig. 2. Built component
Caption: Fig. 3.-5. Distribution of components on the platform
Caption: Fig. 6.-9. Component orientations No.1-No.4
Caption: Fig. 10. Diagram of the costing model [1]
Table 1. Print Times (in minutes)
Processing Times in different Orientations (min.)
Component No. 1
type
[layer.sub.20] [layer.sub.40]
[micro]m [micro]m
Single 239 120
Multiple 1 666 1 037
Large 4 349 2 346
Processing Times in different Orientations (min.)
Component No. 2
type
[layer.sub.20] [layer.sub.40]
[micro]m [micro]m
Single 537 241
Multiple 3 969 2 025
Large 5 158 2 206
Processing Times in different Orientations (min.)
Component No. 3
type
[layer.sub.20] [layer.sub.40]
[micro]m [micro]m
Single 466 218
Multiple 2 887 1 976
Large 4 352 2 195
Processing Times in different Orientations (min.)
Component No. 4
type
[layer.sub.20] [layer.sub.40]
[micro]m [micro]m
Single 478 224
Multiple 3 661 2 300
Large 4 798 2 440
Table 2. Volumes of printed components and their support structures
(in [mm.sup.3])
Volumes in different Orientations
Component
type No. 1 No. 2
Component Support Component Support
Single 3 422 7 665 3 422 3 146
Multiple 68 440 153 302 188 210 173 003
Large 219 002 348 825 219 002 144 872
Volumes in different Orientations
Component
type No. 3 No. 4
Component Support Component Support
Single 3 422 903 3 422 3 840
Multiple 164 256 43 351 164 256 184 344
Large 219 002 29 642 219 002 158 356
Table 3. Sum of costs (in EUR) and share of processing costs in them
Single
Orientation [layer.sub.20] [micro]m
[C.sub.[SIGMA] [C.sub.pt]/
[C.sub.[SIGMA]
No. 1 172 92%
No. 2 364 98%
No. 3 315 98%
No. 4 326 97%
Single
Orientation [layer.sub.40] [micro]m
[C.sub.[SIGMA] [C.sub.pt]/
[C.sub.[SIGMA]
No. 1 94 85%
No. 2 168 95%
No. 3 150 96%
No. 4 158 94%
One of [Q.sub.max]
Orientation [layer.sub.20] [micro]m
[C.sub.[SIGMA] [C.sub.pt]/
[C.sub.[SIGMA]
No. 1 69 80%
No. 2 57 84%
No. 3 46 87%
No. 4 60 84%
One of [Q.sub.max]
Orientation [layer.sub.40] [micro]m
[C.sub.[SIGMA] [C.sub.pt]/
[C.sub.[SIGMA]
No. 1 48 71%
No. 2 33 74%
No. 3 33 82%
No. 4 41 77%
Large
Orientation [layer.sub.20] [micro]m
[C.sub.[SIGMA] [C.sub.pt]/
[C.sub.[SIGMA]
No. 1 3 615 80%
No. 2 3 909 87%
No. 3 3 239 89%
No. 4 3 687 86%
Large
Orientation [layer.sub.40] [micro]m
[C.sub.[SIGMA] [C.sub.pt]/
[C.sub.[SIGMA]
No. 1 2 289 68%
No. 2 1 955 75%
No. 3 1 811 80%
No. 4 2 126 76%
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