Temperature chamber for a test specimen

Abstract

Temperature control chamber for a test specimen (11) or for further processing a workpiece (16), with a wall (1), wherein a chamber interior (2) is connected to a heat and / or cold source (3), wherein an opening (4) is provided, wherein the wall (1) has a test specimen holder (12) extending into the chamber interior (2), characterized in that the wall (1) has a polymethacrylimide layer (5), wherein the test specimen holder (12) is made of the same material as the wall (1), or a conventional test specimen holder has a carbon-polymethacrylimide coating (8).

Description

Technical field

[0001] The invention relates to a temperature control chamber for a test specimen according to the preamble of claim 1. State of the art

[0002] Such temperature control chambers are already known and commonly used in a variety of forms and designs.

[0003] WO 2011 / 020 671 A1 discloses a plastic insulation panel for the manufacture of an insulation system for a building.

[0004] For example, DE 10 2015 117 134 B3 describes a temperature control chamber which, together with a loading device, can enclose a material and / or component sample, thereby enabling optical measurement of the changes in the material and / or component sample under certain thermal and / or atmospheric environmental conditions, with a backlight enabling the realization of a space-saving temperature control chamber.

[0005] Reference is also made to DE 10 2006 038 925 A1. This discloses a device for heating a sample in an apparatus in which a high vacuum can be set. Among other things, a holder for the sample and a heating element are disclosed.

[0006] Furthermore, reference is made to DE 10 2008 009 254 A1, which describes a multi-zone furnace for heating and temperature control of reactors and pipes in apparatus, wherein the multi-zone furnace has a modular design, making it possible to heat and / or cool the furnace or individual zones of the furnace efficiently, with the interchangeable heating cassettes in particular offering the advantage that the reactors and the components connected to the reactors are easily accessible, thus facilitating conversion work.

[0007] Furthermore, reference is made to DE 81 14 171 U1. This patent describes a climate test chamber with controlled temperature and / or humidity for carrying out corrosion tests under fog generation by atomizing a salt solution with the aid of pressurized gas in a spray nozzle, wherein the parts of the test device that come into contact with the spray mist or the test solutions are made of a material that is as unaffected as possible by the test solution or the spray mist, wherein at least one temperature control device has at least one channel through which a heating or cooling medium flows, and the stressed surfaces are made of a plastic that can withstand even the highest test temperature.

[0008] Reference is also made to US 2012 / 0294329A1. This patent discloses a method and an instrument for measuring thermal conductivity, enabling the measurement of very small samples, the measurement of samples with a thermal conductivity on the order of air, and the use of air as a reference material.

[0009] Finally, reference should be made to DE 20 2014 003 439 U1. This patent discloses a testing, inspection, measuring and / or examination device for positioning a measurement object, comprising a sample carrier made of a low-density foamed material, which is fixed or fixable on a base.

[0010] The design of state-of-the-art systems is generally very complex and varies depending on the application and temperature control method. Typically, enclosures containing insulating mats, such as mineral wool or other insulating materials, are housed within a casing, usually made of metal. This layered construction results in thick walls to achieve insulation and low thermal conductivity. Furthermore, internal components such as contacts or mounts for devices or test specimens, made of metal or similar materials, are incorporated into these systems. This leads to increased energy consumption to enable faster temperature control.

[0011] Furthermore, the state of the art employs a wide variety of temperature control methods, such as liquid temperature control systems, air temperature control systems, and forced-air temperature control systems. Each of these systems requires a completely different design for the associated temperature control chamber. Object of the invention

[0012] The object of the present invention is to overcome the disadvantages of the prior art. In particular, a temperature control chamber is to be provided whose walls can withstand high pressure and extreme temperatures. The temperature control chamber should be easy to manufacture and easily adaptable to the needs of the respective user. Furthermore, a temperature control chamber should be provided that can be used unchanged with a wide variety of temperature control methods. Solution to the task

[0013] The features according to claim 1 lead to the solution of the problem.

[0014] Advantageous embodiments are described in the dependent claims.

[0015] The temperature control chamber according to the invention serves to hold and test a test specimen. The test specimen can be various types of sensors or electronic devices. Examples of suitable sensors include radar sensors, infrared sensors, CCD cameras, and many more. Examples of suitable electronic devices include mobile phones, touchpads, computers, computer chips, control panels, and many more. This is an exemplary list. Ultimately, anything that can be tested or examined under specific environmental conditions, such as a particular temperature, pressure, or chemical environment, before actual use is suitable as a test specimen.

[0016] The temperature control chamber consists of a shell, which in turn comprises a wall that can completely or partially enclose, surround, or encompass the test specimen. The wall must exhibit particularly good thermal insulation, temperature resistance, pressure resistance, and damping properties.

[0017] The casing forms a chamber interior. This chamber interior is connected to a heat and / or cold source. This means that the chamber interior can be exposed to different temperatures. The chamber interior can be designed so that the heat and / or cold can be efficiently transferred to the test specimen through designated channels. For this purpose, the wall can, for example, have corresponding bores and channels.

[0018] Furthermore, the temperature control chamber has an opening. This opening serves, for example, to insert the test specimen. It also serves to remove the test specimen after the test has been carried out.

[0019] In the embodiment according to the invention, the wall has a polymethacrylimide layer. Polymethacrylimide is a polymer produced from rigid plastic (PMI) and rigid foam (PMI-E) and belongs to the polyimides. It is normally used in aircraft and automotive manufacturing, medical technology, and lightweight construction. Polymethacrylimide is a material which, according to EP 1 678 244 B1, is produced, for example, by producing foamable cross-linked polymers, in particular by using a mixture of (A) 30-70 wt methacrylic acid, 30-60 wt T Methacrylonitrile, 0-30 wt further vinyl unsaturated monomers, (B) 0.01-15 wt tert-butyl methacrylate and / or tert-butyl acrylate, (C) 0.01-10 wt propellant, (D) 0.01-10 wt T crosslinker, (E) 0.01 to 2 wt polymerization initiators and (F) 0 to 20 wt of usual additives in substance polymerized to a plate, which is optionally tempered and then foamed at temperatures of -250 to +150°C.

[0020] Polymethacrylimide foams (PMI foams) have been known for a long time. Under the trade name ROHACELL® HF®, these foams find many applications, particularly in the field of layered materials (laminates, composites, foam composites, sandwich constructions, sandwiches). Layered materials are molded bodies consisting of an outer face sheet and an inner core material. Face sheets are made of materials that can withstand extremely high tensile forces, either uniaxially or multiaxially. Examples include glass and carbon fiber fabrics or aluminum sheets, which are bonded to the core material with adhesive resins. Core materials with low densities, typically in the range of 30 kg / m³ to 200 kg / m³, are preferred.

[0021] Polymethacrylimide has the advantage of being extremely lightweight and easy to process. It also has a very low thermal conductivity and can be used in temperatures ranging from -270 °C to 240 °C. Another advantage of polymethacrylimide is its ease of processing; simple saws and drills are sufficient.

[0022] Due to the special material properties of polymethacrylimide, all temperature control processes can be carried out in one and the same temperature control chamber without any significant adjustments.

[0023] In another embodiment of the invention, the temperature control chamber serves to dehydrate a workpiece. The temperature control chamber also has a wall, wherein the interior of the chamber is connected to a heat and / or cold source, wherein an opening is also present and the wall has a polymethacrylimide layer.

[0024] The above statements regarding the temperature control chamber for a test specimen also apply to the temperature control chamber for further processing of a workpiece. The same applies to the statements regarding polymethacrylimide.

[0025] However, the temperature control chamber is not designed for testing a workpiece, but rather for curing materials through dehydration and / or heating. Cooling can also be a possible further processing step.

[0026] The temperature control chamber according to the invention is used in development, testing, validation, and production, with no limitations on the size and shape of the test specimens or workpieces. Whether or not temperature control actually takes place within the temperature control chamber according to the invention is irrelevant to its design.

[0027] According to the invention, the temperature control chamber is also used for so-called in-circuit tests or functional tests, or for final testing.

[0028] Depending on the requirements, an adapter or conversion kit may also be used inside the chamber. A conversion kit, consisting of a contacting part (either an upper or lower adapter) and a counter-holding part, establishes a signal connection between the test points / contacts of the device under test and the signal interface of the handling system. The handling system then forwards these signals to a tester-specific interface.

[0029] The temperature control chamber can also be used as a thermal and absorber chamber for radar sensor tests.

[0030] In addition to the polymethacrylimide layer, the wall can also incorporate other materials. For example, the wall can be designed to enclose a hard material on one or both sides. This hard material could be, for instance, a plastic such as carbon fiber. This gives the entire structure a compact and stable design. In one embodiment, the polymethacrylimide layer, which is formed as a plate, is encased on both large surfaces with a carbon fiber layer.

[0031] If the thermal conductivity of the wall needs to be improved even further for specific applications, an aerogel layer can be incorporated into the wall, for example. This improves the thermal conductivity of the wall by a factor of 10 to 100.

[0032] In another embodiment, the wall can have a carbon-polymethacrylimide coating on one and / or both sides. The carbon-polymethacrylimide coating is a conductive, closed-cell foam that is radar-absorbing and electromagnetically shielded.

[0033] The carbon polymethacrylimide coating exhibits all the exceptional thermomechanical properties and strength / weight ratios of the polymethacrylimide coating, but also offers the advantages of superior dielectric properties and absorption of electromagnetic waves at radar frequencies.

[0034] This combination of properties results from loading the polymethacrylimide with carbon particles during processing, creating an excellent sandwich core solution for components requiring, for example, radar absorption properties. This material is marketed by EVONIK® under the product name ROHACELL® EC.

[0035] In principle, polymethacrylimide (ROHACELL® HF®) can be used alone or carbon polymethacrylimide (ROHACELL® EC®) alone or in combination, depending on the needs of the individual user.

[0036] Furthermore, the opening of the temperature control chamber has a door. The door is preferably made of the same material as the wall of the temperature control chamber itself, with the exception that a viewing window may be incorporated into the door if required.

[0037] The temperature control chamber can have a receiving opening in its wall. This is a receiving opening that is recessed into the wall. This is advantageous, for example, when a radar sensor is fitted into the receiving opening in such a way that it is essentially flush with the wall. This is particularly advantageous if the wall also has a carbon-polymethacrylimide coating, so that unwanted radiation effects and false signals cannot occur during testing of the radar sensor. This is the case, for example, when a bracket is present on which the radar sensor is mounted. In such cases, the bracket itself can sometimes cause undesirable reflections. Receiving the radar sensor directly into the receiving opening in the wall minimizes this risk.This setup allows the test object, in the form of the radar sensor, to be temperature-controlled within the temperature chamber without having to temperature-control the external environment. This makes it possible to take the measurements.

[0038] Furthermore, the wall features a test specimen holder extending into the interior of the chamber. The test specimen holder is made of the same material as the wall itself.

[0039] The test specimen holder can, for example, be a true support, contacts, a bed-of-nails adapter, or even a combination of other materials. It is important that the thermal energy is introduced exclusively into the test specimens or workpieces and that the surroundings, the contacts, or the test specimen holder are not unnecessarily heated. This results in a significant increase in the temperature control rate. The overall weight of the system can be considerably reduced while maintaining the same functionality. The temperature control chamber according to the invention also allows the chamber itself to be easily and quickly adapted to the test specimen.

[0040] The test specimen holder or support arm of the radar sensor mount can be coated with the carbon-polymethacrylimide layer by hot forming. Consequently, the test specimen holder consists of polymethacrylimide. Alternatively, a conventional test specimen holder made of, for example, metal, can be coated with the carbon-polymethacrylimide layer. This means that a test specimen holder made of metal or another material simply has the carbon-polymethacrylimide layer as a coating.

[0041] This has the advantage of extremely high rigidity at very low weight and absorption of any unwanted reflections. The rigidity also allows for a reduction in the overall size of the system.

[0042] The chamber wall can also have an insulated inlet. The temperature chamber can also be equipped with a membrane for thermal testing, acting as an insulated inlet. This membrane can, for example, allow a robot finger, or the fingers, hand, or arm of a user, to reach into the chamber interior, protected by the membrane, to operate a keypad under test conditions. This membrane can be made of silicone. An advantage of this design is that no actuators within the temperature chamber need to be temperature-controlled. Furthermore, the outer surface of the membrane—the area outside the chamber interior—can be supplied with tempered dry air to prevent icing or condensation.

[0043] The temperature control chambers can also be equipped with vibration systems. This means that either the wall itself or a vibration sensor mounted on or within the wall is present.

[0044] Sensors can be used in the temperature control chamber to monitor the condition of the test object or material and transmit corresponding signals to a computer to perform an actual / target comparison.

[0045] In particular, this system enables targeted temperature control of specific areas on, in, and around the test object through intelligent airflow within the insulation. This directs the temperature precisely to the area requiring temperature control. As a result, the entire test object does not need to be heated, thus saving costs by reducing cycle times. Energy is also saved because the entire test object does not need to be heated. This allows for zone-based temperature control, for example, on a printed circuit board, where specific areas that must not be exposed to heat are shielded by the insulation.

[0046] Therefore, the test specimen can be exposed to different temperatures in the temperature chamber. For example, one part of the specimen can be exposed to a heating medium, while another part is exposed to a cooling medium. The cooling medium is defined by a temperature difference compared to the heating medium; specifically, the cooling medium has a negative temperature difference. The temperature chamber is equipped with a heating line and a cooling line, separated by an intermediate wall.

[0047] Air can be used as a heat transfer medium, and nitrogen can be used as a cooling medium in the same way.

[0048] The walls of the temperature control chamber, as well as any partitions within it, are made of polymethacrylimide. This allows the partitions to be very thin while still achieving excellent insulation values. The partitions can also be used to cover a second part of the test specimen, protecting it from the heating or cooling medium.

[0049] The heat supply line has a heat inlet and a heat outlet so that the heat medium can flow past the test specimen without causing unwanted turbulence. Similarly, the cold supply line has a cold inlet and a cold outlet. The test specimen's mounting is also made of polymethacrylimide.

[0050] The temperature control chambers described here can be freely combined within the scope of the invention. This applies in particular to individual features that can be transferred from one temperature control chamber to another without impairing the functionalities of the other temperature control chamber. Character description

[0051] Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawings; these show in: Fig. 1 A view from an oblique angle above of a temperature control chamber T1; Fig. 2 a cut side view of a wall according to the invention (1); Fig. 3 a top view of another embodiment of the wall (1); Fig. 4 a side view of another embodiment of the wall (1); Fig. 5 a view from an oblique angle above of another embodiment of the temperature control chamber T2; Fig. 6 a schematic side view of an application example of a tempering chamber according to the invention. Example of implementation

[0052] In Fig. Figure 1 shows a temperature control chamber T1. An enclosing wall 1 is shown. The enclosing wall 1 encloses a chamber interior 2. Furthermore, the temperature control chamber T1 has an opening 4. This opening 4 can be closed by a door 9, the door 9 being located in the Fig. 1 is shown in the open state.

[0053] In addition, in the Fig. 1 to recognize how a heat and / or cold source 3 is present.

[0054] A test object 11, for example a sensor, is to be introduced through opening 4 into the interior of chamber 2 of the temperature control chamber T1 in order to test it there under specific temperatures or to expose it to certain temperatures. This can involve heating or cooling. The temperature range here extends from -250° to +150°C.

[0055] The defined temperature is introduced into the interior of chamber 2 via a heat transfer medium, such as air, liquid, or the like, through appropriately provided channels or the like, whereby this is done in the Fig. Figure 1 is no longer shown. Also shown is a temperature conductor, not described in detail, between the temperature control chamber T1 and the heat and / or cold source 3. This is only one embodiment of other possibilities. For example, it is also conceivable that the heat and / or cold source 3 could be integrated directly into the wall 1 or at least into the temperature control chamber T1.

[0056] In this specific example, wall 1 has a polymethacrylimide layer 5. This polymethacrylimide layer 5 has an aerogel layer 7 in its center to achieve further improved thermal conductivity.

[0057] In the Fig. Figure 2 shows a cutaway side view of a wall 1 according to the invention. This is an exemplary embodiment which illustrates all possible positions of the wall 1 provided by the invention at once, whereby only a selection of the positions shown is also according to the invention.

[0058] On one side, wall 1 points out from the Fig. 2 A hard material 6, for example carbon, is applied to the surface to guarantee a certain strength and stiffness. On the other side, the wall 1 has a carbon-polymethacrylimide coating 8. The carbon-polymethacrylimide coating 8 serves, for example, in radar sensors being tested, to absorb radar beams emitted from a radar source (not shown) in order to test the radar sensor.

[0059] In the Fig. Figure 3 shows another embodiment of the wall 1 according to the invention. A receiving opening 10 is provided in the wall 1 shown there. In the receiving opening 10, in turn, there is a Fig. 3 of the test specimen 11, for example, in the form of the radar sensor. The surface of the wall 1 facing the observer preferably has the carbon-polymethacrylimide coating 8 in such a test setup.

[0060] The Fig. Figure 4 shows a side view of a further embodiment of a wall 1 according to the invention. A test specimen holder 12 extending into the interior of the chamber 2 is provided there. A supply channel 14 is provided in the test specimen holder 12, which, for example, supplies a liquid or gaseous heat medium directly to the workpiece 16 located in a receptacle 15.

[0061] The test specimen holder 12 consists of the polymethacrylimide layer 5, and the test specimen holder 12 can have the carbon polymethacrylimide coating 8.

[0062] The Fig. Figure 5 shows a further embodiment of the temperature control chamber T2 according to the invention, wherein a second opening 13 is provided in addition to the opening 4. This has the advantage, for example, that workpieces 16 or test specimens 11, which are to be introduced into the temperature control chamber T2 for further processing, are transported through the temperature control chamber T2 by means of a conveying system, such as a conveyor belt, at a preset speed in order to achieve a final result or an intermediate result at the specified temperature. The temperature control chamber T2 can also be used for testing test specimens 11. In this case, too, the conveyor belt can, for example, transport the test specimens 11 through the test area, i.e., the interior of the chamber 2, at a specific predetermined speed in order to test the functionality of the test specimens 11.

[0063] In the Fig.Figure 6 shows another temperature control chamber, T3. The view is a schematic, cutaway side view.

[0064] A test specimen 11 is held in the temperature control chamber T3. A first part 18 of the test specimen 11 should be able to be exposed to a heating medium 21 and a further part 19 to be exposed to a cooling medium 22.

[0065] The refrigerant medium 22 is defined by a temperature difference compared to the heat medium 21. Specifically, the refrigerant medium 22 has a negative temperature difference compared to the heat medium 21.

[0066] In the temperature control chamber T3, a heat supply line 17 and a cold supply line 20 are shown. The heat supply line 17 and the cold supply line 20 are separated from each other by an intermediate wall 23.

[0067] In the heat supply line 17, the path of the heat medium 21 is shown by two solid arrows. In the cold supply line 20, the path of the cold medium 22 is shown by two dashed arrows. The heat supply line 17 is operatively connected to a heat source (not shown). The cold supply line 20 is operatively connected to a cold source (not shown). The heat supply line 17 has a heat inlet 24 and a heat outlet 25 so that the heat medium 21 can flow past part 18 of the test specimen 11 without unwanted turbulence. Similarly, the cold supply line 20 has a cold inlet 26 and a cold outlet 27.

[0068] The background might be, for example, that the aim is to simulate the actual conditions of the test specimen 11 in its operational state as realistically as possible. This could, for instance, involve a vehicle camera to be tested, one part of which is located on the vehicle's exterior and the other part inside the vehicle, thus being exposed to different temperature ranges.

[0069] The temperature control chambers T1 to T3 shown in the figure description can be freely combined within the scope of the invention. This applies in particular to individual features that can be transferred from one temperature control chamber to another without impairing the functionalities of the other temperature control chamber. Reference symbol list 1 wall 2 Chamber interior 3. Heat and / or cold source 4 Opening 5 Polymethacrylimide layer 6 Hard material 7 Aerogel layer 8 Carbon-Polymethacrylimide coating 9 Door 10 Intake opening 11 examinees 12 test specimen holders 13 Second Opening 14 Supply line 15 recording 16 workpieces 17 Heat supply line 18 Part One 19 Next Part 20 Refrigeration supply line 21 Heat medium 22 Refrigerant 23 Partition wall 24 Heat inlet 25 Heat outlet 26 Cold air intake 27 Cold air outlet T temperature chamber

Claims

Temperature control chamber for a test specimen (11) or for further processing a workpiece (16), with a wall (1), wherein a chamber interior (2) is connected to a heat and / or cold source (3), wherein an opening (4) is provided, wherein the wall (1) has a test specimen holder (12) extending into the chamber interior (2), characterized in that the wall (1) has a polymethacrylimide layer (5), wherein the test specimen holder (12) is made of the same material as the wall (1), or a conventional test specimen holder has a carbon polymethacrylimide coating (8). Temperature control chamber according to claim 1, characterized in that the wall (1) comprises a hard material (6), in particular carbon, on one or both sides. Temperature control chamber according to one of claims 1 or 2, characterized in that the wall (1) has an aerogel layer (7). Temperature control chamber according to one of the preceding claims, characterized in that the wall (1) has a carbon-polymethacrylimide coating (8) on one side and / or on both sides. Temperature control chamber according to one of the preceding claims, characterized in that the opening (4) has a door (9). Temperature control chamber according to one of the preceding claims, characterized in that the wall (1) has a receiving opening (10). Temperature control chamber according to one of the preceding claims, characterized in that the wall (1) has an insulated inlet.

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