Invention Advice – Keep This In Mind..

The objective of this information is to offer an summarize on strategies which can be used to prototype an innovation making a little volume production operate. This information will not include the techniques in more detail. You will find multiple assets available on the web for each one of the strategies mentioned inside the post. Quite this information will show how to combine the techniques to make a prototype and multiple replicates. By utilizing these strategies or versions, an inventor or business owner would be able to create a prototype and multiple replicates. Furthermore, using the strategies I layed out within a earlier post I published on reduced expenses packaging and inventor or business owner would be able to create a pretty total product that could be check advertised or presented to a possible Inventhelp Careers licensee.

Very first some cautions concerning the strategies layed out below. They may be rather labor intensive. Not hard actual job by itself, nevertheless it does demand learning and building additional skills. Additional, the quantity of replicates that can be created using silicon molds may differ and it is determined by the geometry in the parts becoming molded. Typically the life time of any silicon fungus is different from as few as 25 replicates to several hundred or so. Another factor is just how significantly treatment is consumed in extracting the components. The rougher the fungus is treated the smaller its life.

Furthermore, these strategies are not useful to make complex prototypes including intricate mechanised gadgets. These strategies are definitely more fitted to making prototypes composed of a few elements (1 to 3) with either just one part or in which multiple parts are fixed together.

Ultimately treatment should be consumed in choice of suitable casting materials. Make sure you use supplies that are secure for that prototypes program. Usually do not use harmful supplies particularly in any prototype to be utilized inside the dealing with of food or by children.

Creating the Prototype Design
The routine is the original prototype and will be utilized to create the molds to produce replicates. The strategies which can be used to make an initial prototype include but they are not limited to these layed out below. Use any technique which will produce a usable routine. Please do not truly feel limited to this set of strategies. Feel free to be as innovative in coming up with a strategy to create the routine as you were in creating the idea.

One way to make a prototype routine is to develop the form in wax tart, clay-based or other suitable sculpting materials. The problem with wax tart or clay-based is that they are either breakable (wax tart) or deformable (clay-based). Some clay-based could be fired, heated, so they are will no longer deformable. Nevertheless brittleness continues to be a problem. There some sculpting supplies including Miracle-Sculpt (available at Faucet Plastics) that continues to be pliable for a few several hours and after that treatments to rock and roll hardness. To be able to make the preferred shape sculpting equipment are usually required. Sources for these equipment can be found on the Internet.

Another approach very similar to sculpting is carving. A routine may be whittled away from wooden for instance. If however the content is permeable, the top will have to be closed employing a suitable surface remedy like a sealer or primer. To make the carving job simpler an electronically powered rotary tool may be used. Just like sculpting, options for that equipment and methods related to carving can be found on the Internet.

Fast Prototyping
Usually to utilize a quick prototyping approach a Computer Helped Design (CAD) a few dimensional product is required. This product is exported to some suitable submit structure like a stereolithographic submit. The submit will be read through by a computer automated machine which makes the portion. The procedures are either additive or subtractive. Within an additive procedure materials is extra by solidifying or fusing materials. A computer controlled laserlight may firm up a liquid by a photochemical procedure or adherence of solid materials by sintering or fusing. The part’s position can also be computer controlled. These procedures are known as by a variety of brands including SLA (stereolithography), SLS (discerning laserlight sintering) and FDM (merged deposition modeling). More information are available at the adhering to website

An illustration of this a subtractive procedure is computer numerical controlled machine tooling (CNC). In cases like this the computer controlled machine tool eliminates materials to make the parts.

There are several businesses offering prototyping services. In reality, several SLA businesses have Web sites where the CAD product could be submitted, a value quoted, elements purchased and purchased by way of a credit card payment. The procedure is practically entirely automated. Nevertheless, you will find a verify done around the submitted submit to ensure the motives in the kddwox client. Sometimes there are issues with the submit. On the other hand, the CNC procedure features a lower level of automation. A treatment program needs to be created for that portion product and supply materials needs to be packed in to the machine. The program may be generated by software but as prior to a verify is required to validate motives and fidelity in the submit.

Silicone Molds
After having a prototype routine is completed a silicon fungus can be made using room temperatures vulcanization (RTV) procedure. The majority of the RTV supplies are non harmful and are simple to use. Additional silicon molds will take conditions approximately about 500 levels Fahrenheit and can be use to cast reduced temperatures casting metals including pewter. Since there are Inventhelp George Foreman numerous options on the Web which provide coaching around the approach it will not be included in this article. Materials for RTV molding can be found on the internet and via Faucet Plastics. Nevertheless the adhering to suggestions are available. Very first use safety gloves not just to keep the supplies off the hands but also to keep finger designs off of the prototype routine. The molding materials will be able to produce very good surface details. In case a finger print were around the routine it could get it and it also would show on all your replicates. 2nd, the content is very liquid so ensure your fungus frames are closed. Furthermore, take note of the parting outlines of your own fungus – where the fungus will come apart to remove the casting. Make certain there are no areas where the silicon silicone can stream to trap the portion. For instance, the handle of any glass would demand the fungus would portion on a plane via the middle of the glass and parallel to the handle. There would be handle impressions on both sides in the parted fungus exhibiting a profile in the glass and handle.

Depending on the prototype routine it may be feasible to make a one item fungus which is entirely open up on one area. This sort of fungus is generally employed for reduced temperatures casting metals. For any two item fungus make sure and utilize fungus discharge around the first portion prior to casting the 2nd. If this step is ignored the foremost and next halves will fuse together and tarp the prototype routine. Also for that two portion fungus ensure to not neglect to set the spews along with a load dock. Spews are vents that allow stuck gases to avoid and the fungus is packed till the resin moves away from them. If the casting is defined and the fungus is parted the spews and the load dock will depart a line that has got to be cut off. Therefore make sure you put them in which you can easily contact up the surface. The spews will need to go around the maximum portion of the routine in order that atmosphere is not held in the fungus. Spews and the inlet can be made by sticking rods up and down to the prototype routine and keep them in position having a assisting structure connected to the fungus framework. Within an sticky can be used be sure that it will not hinder the treating in the silicon molding materials.

Use fungus discharge liberally around the relevant areas in the prototype routine and all of areas in the spews and load dock. This is important to make certain that the castings can be removed as well as lengthen the life in the fungus.

To avoid the formation of bubbles on the surface in the prototype routine, paint the top becoming molded using the molding materials. To maintain bubbles from forming in your body in the fungus, pour the silicon ingredient slowly and try to thin the molding ingredient on the lip in the pouring container to burst open bubbles previously inside the materials. It is very difficult to not bring in bubbles while mixing. Usually a vacuum degassing chamber can be used to remove the bubbles. Nevertheless, with plenty of treatment the bubbles really should not be a problem for most prototype styles.

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Ultimately for a intricate a few aspect casting think about a base up method. That is, keep the prototype routine using the top of the the molding framework and load the framework approximately its surface. The routine has to be securely locked in spot or it may drift. Just like the spews and load spout be sure that whatever assisting structure is put in place will not irreparably mar the surface of the casting.

The Electromagnetic Interference of LED Power Supply is not a Problem!

Friends familiar with power circuit design know that in the design process of LED power supply, electromagnetic interference EMI is not a small problem, so how to solve this problem? This article will share the treatment of electromagnetic compatibility from this perspective, so that electromagnetic interference is no longer a problem!

Electromagnetic compatibility (EMC) is the study in electricity of the generation, propagation and reception of unexpected electromagnetic energy, and the harmful effects caused by such energy. The goal of electromagnetic compatibility is the ability of different equipment involved in electromagnetic phenomena to operate normally in the same environment without causing intolerable electromagnetic interference to any equipment in the environment. Traditionally, EMC includes two aspects: EMI (electromagnetic interference) and EMS (electromagnetic sensitivity).

Electromagnetic interference (EMI) refers to any electromagnetic phenomenon caused by conduction or electromagnetic field accompanied by voltage or current that can degrade the performance of a device, equipment or system or cause adverse effects.

LED power EMI, engineers should consider the main aspects: circuit measures, EMI filtering, component selection, shielding and printed circuit board anti-interference design, etc. First, several factors affecting EMC

(1) The circuit structure of the driving power supply

The original LED power supply was linear power supply, but linear power supply lost a lot of energy in the form of heat when operating. Linear power supply working mode, so that he from high voltage to low voltage must have a voltage device, generally are transformers, and then through rectification output DC voltage. Although bulky, heat, the advantage is that external interference is small, electromagnetic interference is small, but also easy to solve.

And now use more LED switching power supply, are IN the form of PWM LED drive power supply is to let the power transistor work in on and off state. On, low voltage, high current; When switching off, the voltage is high and the current is small, so the loss generated on the power semiconductor device is also very small. The disadvantage is more obvious, electromagnetic interference (EMI) is more serious.

(2) Switching frequency

The electromagnetic compatibility of LED power supply is generally the switching circuit in the power supply. The switching circuit is one of the main interference sources of switching power supply.

The switching circuit is the core of LED drive power supply. The switching circuit is mainly composed of switching tube and high frequency transformer. The DU/DT generated by it has larger pulse, wider frequency band and rich harmonics.

The main reason for this high frequency pulse interference is that the switch tube is loaded with the primary coil of high frequency transformer and is a inductive load. Switch pulse spike

Figure 1: Generation of switching pulse spikes

At the moment of conduction, the primary coil produces a large inrush current and a high surge peak voltage appears at both ends of the primary coil; At the moment of disconnection, due to the flux leakage of the primary coil, part of the energy is not transmitted from the primary coil to the secondary coil, and a attenuated oscillation with a peak is formed in the circuit, which is superplaced on the turn-off voltage to form a turn-off voltage spike.

High-frequency pulses produce more emissions, and periodic signals produce more emissions. In an LED power supply system, a current spike is generated by the switching circuit, which also generates a current spike when the load current changes. This is one of the sources of electromagnetic interference.

(3) the ground

Of all EMC problems, the main one is caused by improper grounding. There are three methods of signal grounding: single point, multipoint and mixed. When the switching circuit frequency is lower than 1MHz, single point grounding method can be adopted, but it is not suitable for high frequency; In high frequency applications, multipoint grounding is preferred. Mixed grounding is a method of single point grounding for low frequency and multi-point grounding for high frequency. Ground layout is key. Ground circuit of high frequency digital circuit and low level analog circuit should not be mixed.

(4) PCB design

Proper printed circuit board (PCB) wiring is critical to prevent EMI.

(5) Reset circuit design of intelligent LED power supply

In LED power supply, there are a number of intelligent LED power supply controlled by single chip microcomputer, and some LED power supply by single chip microcomputer control the duty ratio of switch circuit, the watchdog of the single chip microcomputer system for the whole run of LED power supply plays an important role in particular, because all of the interference sources cannot all be isolated or to, once in the CPU interfere with the normal operation of the program, The combination of a reset system and software processing is an effective error-correction defense. There are two common reset systems:


? External reset system. External watchdog circuits can be designed in-house or built with dedicated Watchdog chips. Thus, if the program system is stuck in an infinite loop, and the loop happens to have a “feed the dog” signal, the reset circuit will not be able to perform its intended function.

(2) there are more and more LED power supply with its own on a chip reset system, so users can easily use its internal reset timer, however, some smart LED power supply control circuit reset instruction is too simple, that will also exist such as the infinite loop “dog” instruction, make its loss to the monitoring role.

Second, the hardware processing method of interference measures

To solve the electromagnetic interference problem of LED drive power supply, we can start from the following aspects:

  1. Reduce the interference of switching power supply itself

(1) soft switching technology: in the original hard switching circuit to increase inductance and capacitance components, the use of inductance and capacitance resonance, reduce the switching process DU/DT and DI/DT, so that the switching device when the voltage drop before the current rise, or off the current drop before the voltage rise, to eliminate the overlap of voltage and current.

? Switching frequency modulation technology: by modulating switching frequency FC, focus on FC and its harmonics 2FC, 3FC… In order to reduce the EMI amplitude at each frequency point.

? Selection of components: select components that are not easy to produce noise, conduction and radiation noise. Special attention is usually paid to the selection of winding components such as diodes and transformers. The fast recovery diode with low reverse recovery current and short recovery time is an ideal device for high frequency rectification of switching power supply.

? Reasonable use of electromagnetic interference filter: one of the main purposes of EMI filter, power grid noise is a kind of electromagnetic interference, it belongs to radio frequency interference (RFI), its transmitted noise spectrum is roughly 10KHz~30MHz, up to 150MHz.

In general, differential mode interference is small in amplitude and frequency, resulting in small interference; Common mode interference amplitude, high frequency, but also through the wire radiation, resulting in greater interference. In order to weaken the conducted interference, the most effective method is to install emi filters in the input and output circuits of switching power supply.

LED power supply generally adopts simple single-stage EMI filter, mainly including common mode choke and filter capacitor.

Figure 2 shows commonly used LED power filters. L, C1 and C2 are used to filter common mode interference, while C3 and C4 filter series mode interference. When common-mode interference occurs, the two coils in L have the same magnetic flux direction, and the total inductance increases rapidly after coupling, so the common-mode signal shows a great inductive reactance, making it difficult to pass through, so it is called common-mode choke. Its two coils are wound around ferrite rings with low loss and high permeability. R is the discharge resistance, which can discharge the accumulated charge on C3, so as to avoid affecting the filtering characteristics due to the accumulation of charge. After power failure, it can also make the incoming end L and N of the power supply not charged, so as to ensure the safety of use.

Figure 2: Commonly used LED power filter


?EMI filter can effectively suppress the electromagnetic interference of switching power adapter

In Figure 3, curve A is the waveform of conduction noise from 0.15mhz to 30MHz on the SWITCHING power adapter without EMI filter.

Curve B is the waveform after adding EMI filter, which can attenuate electromagnetic interference by 50 dB (Uv)~70 dB (Uv). Obviously, insertion of EMI filter results in better results. The noise voltage transmitted to the load before and after adding the emi filter is set as U1 and U2 respectively, and the calculation formula is 20lgU1/U2.

The insertion loss is expressed by decibel dB. The higher the decibel value is, the stronger the ability to suppress noise interference is.

The circuit for measuring insertion loss is shown in Figure 3. E is the noise signal generator, Zi is the internal impedance of the signal source, and ZL is the load impedance, generally 50 ohms. The noise frequency ranges from 10KHz to 30MHz. Firstly, the noise pressure drops U1 and U2 at both ends of the load before and after adding EMI filter are measured at different frequencies. Then, the insertion loss value at each frequency point is calculated by substituting the formula 20lgU1/U2. Finally, the insertion loss curve is summarized.

Figure 3: Before and after adding EMI filter


  1. Cut off the transmission path of interference signals;

? Interference from power line can be filtered out by power line filter. A reasonable and effective EMI filter for switching power supply should have a strong suppression effect on the differential mode and common mode interference on the power line.

? Improve the electromagnetic compatibility design of PCB board

PCB is the support of circuit components and devices in LED power supply system. It provides the electrical connection between circuit components and devices. With the rapid development of electronic technology, PCB density is getting higher and higher. The design of PCB has great influence on the electromagnetic compatibility of LED power supply system.

Practice has proved that even if the circuit schematic design is correct and the printed circuit board design is improper, the reliability of LED power supply system will be adversely affected.

PCB anti-interference design mainly includes PCB layout, wiring and grounding, its purpose is to reduce the electromagnetic radiation of PCB and the crosstalk between circuits on PCB.

Figure 4: Proper selection selects the main filter capacitor pin as the centralized ground point

In addition, the frequency of ac sound caused by electromagnetic interference of transformers is generally about 50HZ, while the ac sound caused by improper grounding wiring is about 100HZ due to the frequency doubling of the rectifier circuit, which can be detected by careful differentiation.

The correct wiring method is shown in Figure 4. The main filter capacitor pin is selected as the centralized grounding point, and the strong and weak signal ground wires are strictly separated and summarized at the general grounding point.

Therefore, when designing printed circuit board, we should pay attention to the correct method, comply with the general principle of PCB design, and should meet the design requirements of anti-interference.

  1. Enhance the anti-jamming ability of the interfered body.

In the LED power supply system, the input/output is also the conduction line of the interference source, and the pick up source of the radio frequency interference signal, we generally take effective measures when designing:

(1) The necessary common mode/differential mode suppression circuit should be adopted, and certain filtering and anti-electromagnetic shielding measures should be taken to reduce the interference advance.

(2) As far as possible to take all kinds of isolation measures (such as photoelectric isolation or magnetoelectric isolation), so as to block the propagation of interference.

(3) Lightning protection measures

The LED power supply system used outdoors or the power line and signal line introduced indoors should be considered for lightning protection. Common lightning protection devices are: gas discharge tube, TVS (TransientVoltageSuppression), etc. Gas discharge tube is when the voltage of the power supply is greater than a certain value, usually tens of V or hundreds of V, gas breakdown and discharge, the strong impact pulse on the power line into the earth. TVS can be regarded as two parallel Zener diodes in opposite directions, which turn on when the voltage at both ends is higher than a certain value. It is characterized by transient currents of hundreds or thousands of A.

Therefore, LED power electromagnetic electromagnetic interference control technology mainly includes: circuit measures, EMI filtering, component selection, shielding and printed circuit board anti-interference design. Can solve these problems correctly and reasonably, through the LED drive power supply successfully through the 3C certification, is not a problem!