| RPI's New Inline Test System
with Thermal Chamber |
Finally, a system for true
thermal stress screening that doesn’t require batch loading. Introducing
the new RPI patented Inline Test System™ that allows testing at different
temperatures while powering up your product throughout the system. It's
modular, and can be arranged in many different configurations depending on your
needs.
In the system shown above, modules are arranged in a closed loop
configuration, allowing pallets to make a continuous loop through the system.
They are powered by brush rails throughout, and carry their testing electronics
on top (outside the thermal chambers), so just your products get thermal
cycled. Products are loaded onto fixtured PC boards that extend down into the
chamber’s environment. They can be tested at any point in the system;
allowing testing at any desired product temperature.
We also reduced
maintenance concerns over other conveyor type systems by placing all our
mechanicals for the conveyor system outside the thermal environment.
| 1. Load/
Unlaod |
3. Return/ Buffer
|
5. Ambient
Test |
7. Door
Section |
9. Hot Test |
| 2.
Interface |
4. Inline
Pallet |
6. Shuttle |
8. Chamber |
10. Cool
Down |
Features
- Double door sections between each
chamber to provide maximum thermal isolation.
- Inline Product Load & Unload
Stations, DOA Stations, Multi-level Elevators, Repair loops, Pallet Storage.
- Virtually unlimited test options for
products at hot and cold temperatures.
- Tests multiple types of products at
the same time.
- Provides for rapid product thermal
transition rates. RPI has seen uncased product transition rates of 20º
C/min from +125/-40º C. RPI has also seen cased product transition rates
of 15º C/min over the same thermal range.
- Mechanical refrigeration that is both
reliable and provides for extended operation without LN2 purges or frequent
defrost shutdowns to de-ice the system.
Facilities
Standard power requirements = 480 vac 60
hz 3-phase, actual amp load is dependent upon system makeup (a hot-only system
might require a 200-amp source, whereas a hot-cold-reheat system might require
a 400-amp source plus additional power to the actual refrigeration package)
Control
All sections within the system are
PLC controlled.
- Allen-Bradley brand PLCs are
standard.
- Larger PLCs are SLC500 series using
a 505-processor module that has an Ethernet port should customer wish to
communicate with the specific PLC or entire system.
- Smaller PLCs, if applicable, are
MicroLogix 1200 series.
- A single touchscreen is used for
operator interface.
- Allen-Bradley brand is standard. The
series is PanelView.
- The entire system, as well as each
individual section, may be controlled via the touchscreen.
- Parameters such as temperature,
conveyor speed, process times, and others may be accessible via the
touchscreen. Parameters can be made to be password accessible if desired.
- Alarm information and diagnostics
are displayed when applicable.
All PLCs and the touchscreen within
a system are linked via a local DH485 network.
All sections are SMEMA interfaced
for accurate product transfer.
Safety
- An AC contactor provides a single
E-Stop disconnecting means for incoming 3-phase power.
- E-Stop pushbuttons are located at
operator control stations.
- E-Stop pull cables are provided
along the system for easy access when needed.
- If horizontal shuttles are used,
light curtains and switch-mats are used for the walk-through openings.
- Removable guards are equipped with
limit switches.
Unless otherwise specified by
customer, all sections have visible stacklights to alert personnel as to
status.
Product Power Buss Bars
- Buss bars can be included in various
sections of the Inline System in order to provide power to products within door
sections and thermal chambers.
- Buss bars may also be included in
the load section should a test head be included to connect to newly loaded
pallets for the purpose of performing a process function prior to entry into
the thermal chambers.
Formulas
The following formula can be used
to calculate how many chamber sections are required.
Number of
chamber sections = 5 x (time per pallet shift / required soak time)
The time per pallet shift is the time the pallet takes to
move from one position to the next plus the amount of time the test will take
(this assumes products can be unloaded and a new batch loaded within this time
period). The 5 multiplier represents the number of staging positions per 8 foot
long section.
The minimum number of sections will be the result of
this equation rounded up. There is also a formula for calculating the product
drop rate of the system. This formula is listed below.
Drop
rate = CF x (number of products per pallet / time per pallet
shift)
The correction factor CF accomodates for occasional
pallets gaps in the system. A good approximation for the value in determining
drop rate is around 0.8 to 0.9.
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