Kuhling&Kuhling HT500 User manual

HT500 - Manual
The Kühling&Kühling HT500 3D Printer
General
Welcome to the HT500 3D Printer operating manual of the Kühling&Kühling GmbH (in the following
referred to as Kühling&Kühling).
The HT500 3D Printer (in the following referred to as HT500 or 3D Printer) is a fully automatic stand-
alone device for Fused-Filament-Fabrication (FFF) in a lab or commercial environment.
Any information needed for installing and commissioning, operating, troubleshooting, maintenance
and repair of the 3D Printer are described in the following paragraphs and the accompanying sites.
This user's manual must be read thoroughly as it is meant to provide the operator with all information
needed to operate the HT500 safely and reasonably. Please always provide access to the website for

any user of the 3D Printer in case of questions or problems.
INFO
The HT500 3D Printer is an Open Source project. Any alteration, structural and design changes or
customization for test reasons, optimization and improvement are explicitly requested by
Kühling&Kühling. We would like to support you with your advancements and are looking forward
to receiving your feedback. We will always consider letting your achievements slip in to
constantly improve the HT500. However, please note that Kühling&Kühling cannot be held liable
for damages and injuries resulting from such alterations (see Intended use also).
Valid Version
Hardware revisions
Number of revision from until
v1.4.x 12-2015 current
On the type plate at the rear side of the HT500
you find all information to precisely identify your
3D Printer:
Serial number
Date of manufacturing
Hardware Revision¹
¹ You will also find the valid hardware revision in the
[Setup] menu on the touchscreen.
Type plate on the rear side.
Software versions
Operating sofware:
RepRapOnRails Version v1.3.x → Operating manual
Intended use
The HT500 3D Printer has been designed and built for printing three-dimensional workpieces of nearly
random geometries from common 2.85 mm thermoplastic filament strands.
The 3D Printer features advanced hot-ends with an extrusion temperature up to 500°C. In
combination with the heated build chamber (up to 70°C) and the heated print bed (up to 130°C), this
makes the HT500 suitable for printing a vast scope of materials. It is therefor capable of performing
regular 3D printing tasks with standard thermoplastics as well as special jobs with a variety of
technical plastics.

Contact Kühling&Kühling or refer to our web shop for more detailed information on available and
applicable materials.
The HT500 is intended for industrial and commercial use. It is not valid for the operation in an
explosive atmosphere.
Observing this manual and adhering to the stated information is part of the proper operation.
Improper operation of the HT500 can lead to hazardous situations.
It is forbidden to operate the 3D Printer under conditions and for purposes other than stated in this
manual.
Operating the HT500 is forbidden under the following circumstances:
The HT500 is used for a purpose not designated.
The HT500 or single parts are damaged, the electrical equipment has been installed improperly,
or the isolation is defective.
The HT500 does not function flawless.
Mechanical components or the control system have been inexpertly altered or reconstructed.
Operating parameter have been altered inadmissibly.
Operation with unspecified materials.
Use of unspecified tools.
Failure to regularly perform the prescribed maintenance work.
Operation in an explosive atmosphere.
Warranty terms
The general terms and conditions of Kühling&Kühling GmbH apply. The customer is familiar with these
terms latest on the day of signing the purchase contract.
The warranty terms and the liability period can be found in the contract documents and in the order
confirmation.
Warranty claims and liability are voided in one or more of the following applies:
unintended usage of the HT500
false setup, commissioning, operation
repair or maintenance
operating the apparatus with defective,
missing, improperly installed and/or
malfunctioning equipment.
unauthorized or inadmissible alteration of
the electrical or mechanical equipment or
the operating parameters of the
apparatus.
use of other than the specified
replacement parts, tools, and/or operating
materials
INFO
Any unintended use or structural alteration
of the HT500 not agreed upon with and
approved in writing by Kühling&Kühling
render the warranty and the EU Declaration
of Conformity void and free
Kühling&Kühling from product liability. Even
if approved, alterations have to be carried
out by the customer thoroughly and
properly. If necessary, adequate safety
devices have to be installed.

exceeding the specified maintenance
intervals
cases of disaster and force majeure
Ordering wear and spare parts and material
Wear parts must meet the technical specifications defined by Kühling&Kühling. Kühling&Kühling
original parts are subject to rigid requirements and meet these standards. A complete list of available
wear and spare parts and suppliable materials can be found at our web shop together with an order
form.
Life cycle
Find everything you need to know after you ordered your HT500 3D Printer in the following
paragraphs. From the day of your invoice until the day you want to dispose of the apparatus and
anything in between is explained here.
Delivery
The HT500 3D Printer arrives at your place fully assembled and can be commissioned directly after
setting it up and connecting the power supply.
The 3D Printer is delivered in a wooden transport box on a palette. It is advisable to leave the HT500
packed and on the palette until moving it to its final installation site for commissioning.
At the installation site, unpack the HT500 according to the information in the accompanying Quick
Start Guide.
Dispose of the packaging in accordance with the local waste disposal regulations.
After unpacking, inspect the apparatus for:
damage in transit
completeness of the delivery (compare delivery note)
If you notice any deviants, please immediately inform the hauler and the manufacturer. Do not put
the HT500 to use with defective parts.
Transport
To avoid injuries and property damage observe the following notes when transporting the HT500:
The apparatus' weight exceeds 50 kg. Always carry it two by two.
Keep the HT500 horizontal to avoid damaging internal parts.
Avert shock loads to the housing.
The HT500 has been designed for stationary

application. It is not equipped with special
transport devices such as lifting eyes or handles.
The feet provide sufficient clearance to lift the
apparatus and carry it to the installation site.
While the HT500 is packed and on its transport
palette, use a lifting cart or pallet stacker for
transportation. Make sure that the weight is
evenly distributed and secure the HT500 against
tilting.
INFO
The housing is not designed for
subsequently attaching lifting eyes. If you
need to transport the 3D Printer longer
ways, load and secure it on a stable pallet
and transport it with a pallet stacker or
lifting cart.
Detailed information about safeguarding
and packing the 3D Printer for shipping can
be found in the Service Guide.
Storage
If the HT500 must be stored away, choose a leveled storage site and make sure that the 3D Printer
does not stand on a ledge.
Before storing it, clean the HT500 and protect it from dust with a plastic tarpaulin or air cushion foil.
NOTICE
Do not cover the 3D Printer with a textile sheet since the fibers may enter the supply system and clog
the nozzles after recommissioning. Use lint-free plastic sheets only.
The storage ambient conditions for the HT500 and its components are stated in the data sheet. For
recommissioning after lengthy periods of storage follow the information given in initial
commissioning.
Environment, recycling and disposal
When used as intended, the HT500 presents no environmental danger.
However, the internal cooling works with a coolant that can be environmentally dangerous when
leaking (see data sheet). Please observe the manufacturer's safety data sheet when handling the
coolant.
The materials used for printing can also be environmentally dangerous when handled improperly.
Always observe the manufacturer's safety data sheet and process plastics only within the limit values
specified therein and with respect to the safety instructions.
Generally, consider the environment: the auxiliary and operating materials of the HT500 can be
dangerous to environment and health.
Awareness and foresighted behavior help avoiding ecological and personnel damage.
Components may bear valuable elements such as rare earths, or may be reusable. Do not waste them
by inadequate and thoughtless disposal.
Environmentally hazardous substances must not trickle into the soil or enter the sanitation. They
must be stored in suitable containers and be disposed off adequately and in accordance with local
and national regulations.

The HT500 is recyclable due to its low-pollution
equipment. Nonetheless, the European Guideline
2002/96/EG (Waste Electrical and Electronic
Equipment - WEEE) and the German Elektro- und
Elektronikgesetz (ElektroG) forbid the disposal of
the apparatus via the household garbage. For
environmental friendly recycling and disposal of
the HT500 please contact a certified electronic
waste management professional.
INFO
Kühling&Kühling emphasize that there is no
redemption obligation in this regard.
Personnel safety and device reliability
The HT500 features state-of-the-art design and construction and has been built and tested thoroughly
so that it is safe and ready to use at delivery. Nonetheless, hazardous situations may appear due to
the production process itself and property damage may be caused by false operation.
The risk of experiencing hazardous situations is increased by:
Using the HT500 for other applications than the intended.
Inappropriate usage of the 3D Printer.
Operating the 3D Printer in a non-safe state or under improper conditions.
Insufficient attention, lax handling or intensive soiling.
Therefore:
Use the HT500 for its intended use only.
The HT500 must be in goor working order
and in a safe state at any time. Check the
apparatus prior to every commissioning
and at regular intervals for wear, damage
and cleanliness.
Ensure that nobody can be injured by
parts of the 3D Printer.
Fix any error condition or visible damage
immediately. If prompt rectification is
impossible, decommission the 3D Printer
and do not put it back to use unless all
problems have been solved.
Regard the local accident prevention
regulation.
Provide access to the operating manual for
anybody operating the machine.
INFO
The manufacturer cannot be held liable for
injuries and damages due to inappropriate
usage of the HT500.
Inappropriate usage of the HT500 voids the
manufacturer's warranty.
Injury risks

Some hazards are design related and cannot be avoided by mere constructive measures. To avoid
injuries it is necessary that the operator is aware of such situations and takes adequate care. It is the
owners responsibility to ensure that every user of the 3D Printer is informed about risks and
preventions and that the safety precautions are observed. Access to this manual must be provided at
all times.
The safety advice given in the following is meant to protect the operator of the HT500.
Electrical safety
The HT500 is operated with 110 to 230 V (DC). Touching current-carrying parts can be life-
threatening and cause severe injuries.
Only connect the 3D Printer in accordance with the specifications given in the data sheet.
Works on the electrical equipment of the HT500 and on the power supply system may only be
carried out by skilled electricians.
Always disconnect the 3D Printer from the power supply by switching the main switch off and
removing the mains plug from the socket before carrying out maintenance, repair or cleaning.
Check the condition of cables and isolations at regular intervals and replace damaged parts
immediately.
Do not setup and operate the 3D Printer in a humid environment.
Hot surfaces
Outer surfaces of the HT500 are adequately isolated and do not exceed temperatures of +40°C
(104°F). They are safe to the touch at any time.
Inside the build chamber, the heating elements generate the necessary ambient temperature for
warp-free printing.
Depending on the processed material, surfaces inside the build chamber can reach temperatures
up to +70°C (158°F).
The print table is heated separately, also to minimize warpage. It can reach temperatures up to
130°C (266°F).
The extruder nozzles are heated to melt the filament strands and may reach temperatures of
500°C (932°F).
Touching heated components may lead to grade 1 burning injuries, in case of the nozzles of grade 2
of limited size.
To avoid burning injuries:
Do not open the build chamber during or immediately after completion of a print job.
Always switch off the preheating and wait until the print bed temperature indicated on the
touchscreen has dropped below 50°C (122°F) before removing the print bed. This is also to
avoid stress cracks due to sudden temperature drop.
Some tasks require handling at operating temperature (e.g. changing the nozzle tip). Wear
adequate protective gloves when handling hot components.
Observe the procedures and waiting times stated in this manual.

Coolant
For proper operation the HT500 is equipped with a closed loop low-maintenance cooling system that
needs little interference. The circuit is filled with coolant type Innovatek Protect IP ready-to-use.
If it is necessary to perform works on the cooling system, such as refilling coolant or exchanging
defective hoses, avoid direct skin or eye contact. Always wear adequate protective gloves that are
resistant to chemical substances (e.g. PVC, NBR).
Observe the information provided in the manufacturer's safety data sheet.
Additional information concerning the cooling system and required maintenance can be found in the
Service Guide.
Noise
The HT500 3D Printer is build to be operated in a professional environment such as workshops and
laboratories. It is not suited for the operation in an office. During print jobs, it does not exceed
60dB(A), which is considered “unauspicious” for long-term exposure.
Special noise protection equipment is not required.
Fumes
Molten plastics may emit unpleasantly smelling fumes. The HT500 3D Printer is equipped with an
activated charcoal filter element to reduce such fumes. It is mainly to reduce smells and does not
protect from toxic fumes that evaporate from overheated plastics. Such fumes can be perilous.
It is vitally important not to exceed the temperature limits stated for a printed material. Overheating
is indicated by discoloration and coking.
Emergency stop
You will find a red Emergency STOP button in the top-right corner of the touchscreen. In case of any
unexpected performance of the 3D Printer, press this button to immediately stop any mechanical
movement in the build chamber and to shut down all heater elements.
NOTICE
The emergency stop function does not provide a cool down sequence. Do not use the emergency stop
button to abort current print jobs, because this may lead to damage of the 3D Printer due to
uncontrolled heat accumulation.
Do not use the main switch as an emergency stop button. You risk loosing or corrupting data.
When the emergency stop is triggered, the
microcontroller board responsible for the stepper
motors, heaters and sensors is reset
immediately and returns to idle state afterwards.
Now it is safe to resolve any problems or defects
in the build chamber.

The build chamber can then be reactivated via
the [Print] menue.
Detailed information are provided in the
Operating manual.
The emergency stop button in the top-right
corner of the GUI will immediately stop all
movement and set the 3D Printer in a safe state
for troubleshooting.
Operator qualification
Operating and service personnel must be familiar with the information provided in the manual.
Special training and qualification are not required for operating the 3D Printer. Works on the electrical
equipment and connections of the 3D Printer require profound knowledge of electrics and electronics.
Personal protective equipment
During normal operation it is not necessary to wear special protective gear. Some tasks however
should not be performed without taking protective measures. Situations that require protective
equipment are specially indicated. It is the owner's obligation to provide adequate protective
equipment.
Product reliability
False handling of components can lead to loss of production due to property damage; therefore we
strongly recommend following the information given in this manual.
Extruder nozzles
The brazen extruder nozzles are sensitive to heat treatment and mechanical strain.
If the nozzles or extruder barrels are clogged by congealed material, reheating during the normal
production flow is utterly sufficient to clear them in most cases.
In case you want to change the material type or clogging is effected by foreign particles (i.e. dust
grains dragged along with the filament), it is necessary to remove congealed material from the
nozzles. The corresponding description can be found in the cleaning recommendation.
NOTICE
Do not use mechanical tools or open flames to remelt or remove residues in the nozzles. Overheating
may induce easing of tensions and deformation. The nozzle is then no longer usable for printing.
Structural and functional description
The following paragraphs name and explain all components of the HT500 to give you an exact
overview. The terms are used consistently throughout this manual and will help you identifying any
part you may wish to find or order as a spare part.

Functional principle
The HT500 3D Printer uses the Fused Filament
Fabrication (FFF) process to build up workpieces
in subsequent layers of 0.10 to 0.60mm
thickness. The plastic filament is heated in the
nozzle to its melting temperature and
continuously conveyed by a cogwheel. The
molten plastic is pressed through the bore of the
nozzle tip and onto the heated print bed. After
each layer the print bed is lowered by the preset
layer height and the next layer is applied. The
heat of the newly applied plastic ensures an
adequate binding of the layers.
All temperatures and movement commands are
provided by the GCODE, a file format previously
generated with a “slicing” software. This file
contains all information for a single print job and
is uploaded to the 3D Printer via the web
interface. All Kühling&Kühling 3D Printers are
built to operate best with Slic3r, an OpenSource
Software designed for professional 3D printing.
After the workpiece has been finished the user
can leave it in the heated build chamber to
slowly cool down thus reducing shrinkage and
internal tensions, or he can immediately remove
it and start the next print job. The layered
building process enables the user to create even
complex forms that otherwise could not be
realized.
The layer-by-layer build-up of random
geometries becomes possible with FFF-3D
Printers.
Hardware components
No. Description
1Build chamber
2Electronic chamber
3Touchscreen
The HT500 is built on an aluminum framework
covered with acrylic panels. Its main functional
sections are the upper build chamber and the
lower electronic chamber. The build chamber is
covered with translucent plates to provide
insight during production. It contains all
mechanical components, the air filter. At the
back cover, the filament supply is installed.

The lower is covered with opaque sheets and
contains the electronic components and the
mains adapter. All connections and the power
switches are located here and the touchscreen
for operation is mounted at the front cover.
All covers are fixed to the frame with M4x20
hexagon socket screws and hammerhead nuts,
thus being easy to remove and making all
around access possible to all parts if required.
General overview of the HT500 3D Printer.
All references concerning directions are defined
throughout this manual as follows:
Tag Aspect Description
FFront
Standing in front of the 3D Printer's
touchscreen and looking inside the
build chamber. This is the
reference view for all other
directions.
LLeft Left side of the 3D Printer, referred
to the frontal view.
RRight Right side of the 3D Printer,
referred to the frontal view.
BBack Backside of the 3D Printer, referred
to the frontal view
All movement directions of the axes are defined
throughout this manual as follows:
Tag Called Movement direction
X⊕ X positive Extruder head moves to the
right.
XΘ X negative Extruder head moves to the left.
Y⊕ Y positive Extruder head moves
backwards.
YΘ Y negative Extruder head moves forward.
Z⊕ Z positive Print table moves down.
ZΘ Z negative Print table moves up.
Directions and aspects of the 3D Printer. All
statements refer to the frontal view.
All movements of the extruder drives are
defined throughout this manual as follows:

Tag Called Movement direction
⊕extrude
Left extruder → counter-clockwise
rotation
Right extruder → clockwise rotation
Θretract
Left extruder → clockwise rotation
Right extruder → counter-clockwise
rotation
Movement directions of the extruder drives.
Build chamber
No. Description
1 Extruder head
2 Print table
3 Heating elements (covered) and fans
4 Activated carbon filter with fan
The build chamber is the main production area
with the vertically moving print table and the
two-directional horizontally moving extruder
head inside.
All electrical motors are installed at their
working point and equipped with a water cooling
system. The extruder head moves on an H-
frame, tooth-belt-driven by two separate stepper
motors in X- and Y-direction. The print table is
lifted and lowered in Z-direction by a spindle
drive.
For regulating the temperature inside the build
chamber two heating resistors in separate
housings heat the air which then is circulated
through the chamber by the fans.
Cables and hoses are installed in and guided by
cable carriers.
To minimize air pollution from dissolved
substances, an additional fan circulates the air
through a filter element filled with granules of
activated carbon.
The access to the build chamber is the
Inside view of the build chamber.

magnetically closed double door at the front.
No. Description
5 Filament supply
The filament spools that provide the necessary
material are installed at the rear of the build
chamber next to the filament feed unit.
Filament supply unit at the rear side of the build
chamber.
Extruder head components
No. Description
1 Carriage
2
Left (primary) hot end
for standard single extruder prints (see 9 -
19)
2a
Right (secondary) hot end
for dual extruder prints (multi-color or
multi-material)
3 Filament drive gear
4 Idler lever (release function)
5 Spring tensioning screw M4x20
6 Idler spring
7 Filament feed hose
8 Cooling hoses
The extruder head is mounted to the traverse of
the H-frame and moves horizontally in X- and Y-
direction with useful operating ranges of X =
200 mm and Y = 185 mm.
It contains the filament drive gears forwarding
the filament strands and the hot ends which
melt and dose the material onto the print table.
The filament is supplied through a hose from the
filament supply and is clamped between the
idler lever and the filament drive gear. The
filament drive gear is rotated by the filament
feed motor and thereby forwarding the filament
strand.
Each hot end is provided with its own filament
Extruder head components

strand, thus enabling bicolored prints, printing
two materials or two objects simultaneously or
printing with different extrusion thicknesses (e.g.
for outer contours and inner filling structures).
The left (primary) hot end is configured for
standard single-extruder prints and is the
reference nozzle for leveling the print bed. The
right hot end is only leveled passively after the
print bed has been aligned correctly with the
primary hot end.
No. Description
9Aluminum hot-end mount (cooling block)
with thumb screw and cooling hose adapter
10 Stainless steel barrel
11 Nozzle (0.35mm preinstalled at delivery)
12 Ceramic 500°C heating cartridge with
integrated thermocouple
Each hot-end is heated by a ceramic heating
cartridge so that the filament is molten inside
the nozzle. The integrated thermocouple
provides direct alignment of set and actual
temperature.
To improve the thermal control of the melting
process the hot-end mount is connected to the
cooling system, ensuring an even temperature
distribution in a well defined area of the nozzles
so that there is a preheating zone and a melting
zone. Extruder head components
The nozzle is exchangeable to provide different
bore diameters for different materials, layer
thicknesses or print speed. Ex factory, the
0.35mm tip is preinstalled. Additionally, three
nozzles with diameters of 0.25mm, 0.5mm and
0.75mm are included. The tips are
distinguishable by the engraved markings.
The 0.35mm and the 0.5mm nozzles should be
used for most purposes and can be operated at
an extrusion speed of up to
60mm/s. The Slic3r profiles provided by
Kühling&Kühling are optimized for the 0.35mm
nozzle. Additional information can be found in
the Service Guide and in the Slic3r manual.
Please try and find the settings best suited for
your task. The Slic3r profiles will be constantly
updated and extended.
The 0.75mm nozzle is primarily intended for
Markings to distinguish nozzle sizes.

experimental usage and should only be used
with a max. extrusion speed of 20mm/s for a
start. Adjust the extrusion speed stepwise until
optimized for your needs.
The 0.25mm nozzle is for filigree, thin walled
extrusions. Do not exceed an extrusion speed of
35mm/s since the material throughput will not
suffice for higher speeds.
Print table and print bed
No. Description
1 Elevator assembly
2 Removable 1.8mm PEI print bed
3 Bulldog clamp
4 Heated print table
The print table is mounted on the crossbeams of
the elevator assembly which is positioned
accurate to the millimeter in Z-direction in its
useful operating range of 280mm by a spindle
drive.
The print table itself consists of an aluminum
sandwich panel with a silicone rubber heating
pad that provides temperatures of up to 130°C,
providing an even temperature distribution and
ensuring optimal adhesion throughout the
printing process.
Print table and print bed fastened with four
bulldog clamps
No. Description
5Set screws of the spring-mounted 3-point
leveling support
It rests on three springs lockable with set screws
for an even and accurate leveling since a
precisely adjusted distance between print bed
and nozzle tip is vital for the print bed adhesion
an the print results.
The semi-automated leveling process is
described in the Operating Manual. Additional
information on leveling can be found in the
Knowledgebase.
Print jobs are executed on the removable print
bed laid on the print table and fixed with four
bulldog clamps at the corners. This fixation
allows the use of print beds of different
thicknesses.
3-point leveling support

The print bed can be exchanged for every print,
thus minimizing interruption times during
production.
The standard print bed included in the delivery is
a 210x210x1.8mm polyetherimide (PEI) glass
fabric plate that provides excellent adhesion for
a large variety of materials, including ABS,
Nylon, PET, PC, HIPS, TPU and other.
Important print bed knowledge
The PEI glass fabric composite print beds are, in accordance with the HT500's standards, optimized
for printing ABS and are custom-made to Kühling&Kühling specifications. Due to the manufacturing
process, they may show bends and curves which can make handling them a bit tricky. These flaws are
accepted due to the superior properties of PEI compared to other subsurfaces when printing ABS. It
also works fine with HIPS, PET-Copolyester, PVA and thermoplastic urethane (TPE-U). Other materials
may require a different subsurface, be it another material or a special treatment with tape or glue.
PEI is highly resistant to a lot of solvents which makes it a suitable subsurface for a lot of materials
since removing residues and refurbishing for the next print becomes quite easy.
Find more information about the custom-made Kühling&Kühling PEI print bed:
Operating and handling are described in the Operating manual.
Cleaning and care can be found in the Service guide.
Read about materials and printing subsurfaces in the Knowledgebase.
Drives
No. Description
1 X-axis motor (extruder head motor)
2 Y-axis motor (H-frame traverse motor)
3 Z-axis motor (spindle drive of print table)
4 Filament feed motors (filament gear drive)
Five electrical stepper motors, one per direction
of the extruder head, one for lifting and lowering
the print table and one per extruder head nozzle
for forwarding the filament, provide all
necessary movement for printing. All motors are
equipped with water cooling to prevent
overheating due to workload and the heating of
the build chamber.Single views of the drive motors.
Sensors
Sensors for positioning and temperature control

are installed inside the build chamber.
Every axis is equipped with a Hall effect sensor
and a magnet for accurate home positioning. If
the Hall effect sensor nears the magnet and
measures the defined threshold value of the
magnetic field strength, the sensor effects a
“stop” signal via the microcontroller. After all
sensors have given this signal the moving axes
are in home position. The home position is the
reference value for all relative movement of the
extruder head and the print bed.
Hall effect sensor and magnet of the X-axis.
Hall effect sensor and magnet of the Y-axis.
Hall effect sensor and magnet of the Z-axis.
Thermistors measure the relevant temperatures
for the printing process, i.e. the print bed
temperature and the build chamber
temperature. All thermistors deliver their input
signal to the microcontroller and thus effect
switching on and off the according heating
resistor.
The print bed temperature is measured directly
at the heating pad with which it is looped in a

control circuit.
The build chamber sensor is installed at the
elevator assembly and measures the air
temperature inside the build chamber. Its
measurements influence the control of the
heating resistors inside the heating elements.
The extrusion temperature is measured directly
at the heating cartridge by an integrated
thermocouple.
Thermistors of the print bed (1) and the build
chamber (2).
A limit switch is installed at every filament inlet of the filament feed unit
(see below).
Filament supply
No. Description
1 Feed unit
2 Filament spool carrier
3 Filament spool (2.3 kg)
4 Limit switch
5 Filament inlet with dust wiping sponge
The HT500 is designed for printing filament
strands of a diameter of 2.85 mm with a
tolerance of ±0.1 mm. More information about
filament and materials can be found in the
material section and the print preparation
section of the Knowledgebase.
Two separate strands can be fed from the
outside to the extruder head. One filament spool
can be positioned on each spool carrier; a stop
collar prevents them from falling down due to
their rotation.
The end of the filament strand is manually
inserted into the inlet of the feed unit and led
through hoses to the two extruder nozzles. At
the inlet the filament is put through a sponge
that wipes dust off the strand to keep the
material unsoiled before reaching the nozzle.
A limit switch registers the end of the filament
strand when the spool is empty. The print
process then is interrupted and the lack of
material is signaled on the touchscreen. The
printing process can be resumed after refilling
Filament supply

the supply. Filament inlet with limit switch and dust wiping
sponge.
Wiper
No. Description
1 Wiper lip
2 Bracket
3 Excess retainer
4 Mounting arm
The HT500 3D Printer is equipped with a wiper to
enable high-quality dual extruder printing.
During every tool change of a dual-extruder
print, the nozzle to be used next will be primed
and wiped to ensure pressure loss during its
pause time is compensated and the nozzle starts
well filled.
The wiper makes sure that the nozzle tip is
always clean and well filled after a tool change
during dual-material print jobs.
Electronic chamber
No. Description
1RADDS v1.5 3D Printer Driver Shield
2UDOO Quad Single Board Mini PC
3 3V power supply for internal real-time clock
4 Solid State Relays on cooling substructure
5 12V(DC) Mains Adapter
All control elements are installed in the
electronic chamber together with the 12V(DC)
mains adapter and the cooling unit.
The chamber is completely covered with white
acrylic sheets fastened to the aluminum frame
with hexagon socket screws and hammerhead
nuts.
The RADDS 3D Printer Driver Shield in
conjunction with the SAM3X microcontroller on
the UDOO board controls all processes of the
printing process, i.e. the drives, the heating
resistors, heating fans and the temperature
sensors. Exchangeable hardware components
are the stepper motor drivers.
The UDOO Quad Single Board Mini PC provides
the GUI of the touchscreen and the ethernet
connection and processes the G-codes of the
Inside view of the electronic chamber (left side).

slicing software.
Slots in the bottom cover provide an air inlet for
the cooling unit.
When the 3D Printer is switched off the internal
real-time clock of the Mini PC is fed by two
external batteries so that the system's time
signal is not lost.
The solid state relays switch the four heating
resistors of the build chamber heating and the
heating resistor of the print table.
No. Description
6 Cooling unit radiator
7 Cooling unit pump
The cooling unit consists of a pump with water
reservoir, a radiator and the closed loop coolant
circuit filled with an electronic cooling liquid. It is
automatically switched on and off when the build
chamber is activated/deactivated.
The coolant is pumped in a circle past the
motors and the extruder nozzles where it
absorbs heat which is then emitted via the
radiator.
Check the coolant level monthly and if required,
refill as described in the Service Guide.
Inside view of the electronic chamber (right
side).
No. Description
8 Type plate
9 Cooling unit radiator grill
10 Mains plug
11 Main switch
12 RJ45 ethernet plug
13 230V supply cable with Schuko plug
At the rear cover you find the mains plug and
the main switch of the mains adapter and the
RJ45 ethernet plug for the network connection.
The cooling systems' accumulated warmth is
dissipated via the radiator grill to the outside.
The type plate is positioned next to the fixing
screws of the cooling water pump.