| Electronics > Projects, Designs, and Technical Stuff |
| Counterfeit products, or not? |
| (1/3) > >> |
| NaxFM:
Hello guys, it has been months that I thought of a project that I would like to sell, and today I decided finally to work on it. The main goal is to sell it, so I want components from reputable brands and reliable sources, I would really like to avoid components smoking and catching fire once in the house of the customer. One of the most important one is a bipolar stepper driver, and I figured that an allegro A4985 would be perfect. On digikey, if I buy a thousand of them (which is really a LOT to start), the unit price is 1,52 dollars, fair enough. The doubt is that on eBay and aliexpress, they sell entire pcb modules, already assembled with the required resistor and capacitors, at prices as low as one dollar or less, and they use the allegro a4988, which costs more than the A4985. I'm sure you saw them before, they're the typical stepper driver modules for 3d printers. The price is so ridiculously low that I'm almost sure that they use counterfeit chips, but I want to ask you if they are really fake chips or they are actually original ones. I figured that maybe they have such a low price because they sell millions of them, I'm not really sure... Obviously I want to build my product as cheap as possible, and if these modules aren't fake, then I don't see the point in spending 1.5 dollars on just the chip... |
| janoc:
This has been debated to death already. In short: - A lot of those modules use fake/relabeled/compatible Chinese chips - Thousand pieces of something is nothing. For A4985 it is not even a full reel! If you order 10-100k then the distributors and manufacturers start to be interested and you get very different prices. - The module manufacturers aren't buying components for Digikey prices (Digikey has a very non-trivial margin!). If a factory somewhere in China buys a 100k pieces of something directly from the manufacturer (which often has the factory literally next door!) they aren't going to pay prices you see on Digikey but much less. And surplus/rejects then tend to wind up being sold for pennies on Shenzen markets (and then eBay/Ali/etc. inside these various modules). Some may work fine, some may be rejects that sort of work (e.g. had STM32F103s that worked inside a cheap STLink clone but wouldn't reliably work with custom firmware. A fresh chip bought from RS had no issues.) - If you hope to compete with China on price, you will go bankrupt. In that light penny-pinching on a motor driver for a small series production is silly, especially if you buy some who knows what quality parts from China and get your margin wiped out by returns. If you want to save no matter what and still keep the risk reasonable, look at e.g. LCSC and some of the Chinese components - there may be something similar to the Allegro driver and possibly quite a bit cheaper. For example HR4988 - which seems to be an exact clone of your A4988 and costs $0.40@30 pieces ... https://lcsc.com/product-detail/Motor-Drivers_HR4988_C128662.html I hope that answers your question how is it possible that the eBay modules are so cheap. |
| Seekonk:
I like to think of them as copies. A lot of technology isn't hard to copy. If it isn't a circuit designed right on the edge it may not matter. You may find it economic to test devices to come in. That said, I just got a 100 TL431, a jellybean part, and all were not working except 5. And those 5 were out of spec. One had a lead defect which all leads me to believe these all came out of a sorting machine. Stuff is cheap if it doesn't have to be handled and stored. You got 3 cent microprocessors. |
| NaxFM:
--- Quote from: janoc on September 22, 2019, 02:30:23 pm ---This has been debated to death already. In short: - A lot of those modules use fake/relabeled/compatible Chinese chips - Thousand pieces of something is nothing. For A4985 it is not even a full reel! If you order 10-100k then the distributors and manufacturers start to be interested and you get very different prices. ... --- End quote --- Thank you a lot! That's all I needed to know! I wanted to keep the production cost as low as possible because what I'm doing is a modular design, and can be comprised by many modules, so a saving of one dollar a module is really a big deal for me. Of course I don't want to compete with China, I'm designing a product which needs different stepper drivers, but it's not for 3d printers, CNCs or something similar, I know that it's impossible to compete in a market ruled by China. I'll check what lcsc has to offer, thank you again! |
| NaxFM:
--- Quote from: Seekonk on September 22, 2019, 02:31:46 pm ---I like to think of them as copies. A lot of technology isn't hard to copy. If it isn't a circuit designed right on the edge it may not matter. ... --- End quote --- Of course, but can you trust cheap copies when it comes to safety and fault protection? For my 3d printers, I've been using for years stepper drivers which were basically free, but I know what I'm getting into and I take full responsibility for my choice. But if I had to sell 3d printers that I made, I really wouldn't take any chance that someone could sue me because the power electronics went on fire and burned his beard after a short in the motor windings... |
| Navigation |
| Message Index |
| Next page |