Does anyone know of any common anti vibration electronic connectors that will maintain the connection even if you wiggle the connector?
For connectors that have to connect and damn the cost, here’s what I use:
A (much) more economical choice is a DB style (9 or 15 or 25 or whatever works for you) connector. They’re rated for 5A per pin and you can double up pins to some degree to get more power (there is a total current limit for the connector but I forget what it is). I only use the gold plated, crimp pin termination style because my company is buying and connector failures are not an acceptable excuse for losing a $100K+ platform. However, if you are a competent solderer and can’t justify the added reliability of a $250 crimp tool, the solder termination style may be acceptable. I don’t use a back shell because space is limited in my systems but I definitely screw the mating halves together with standard 4-40 hardware and split lock washers and Loctite if I’m really paranoid (which I am).
As Gene pointed out, D type and using the type with the fixings, they will be ideal.
The images below are from a 20+ year old ROV system that uses D type that suffers from severe vibration due to the thrusters operating and this keeps them rock solid.
@ Gene - $15 dollar connectors, wow.
I settled on Ditto Wire-To-Wire Connectors for now, but I hope to find a less expensive (like 10 dollars less) connector that @ Gene mentioned.
@ Dave McLaughlin - So many pots! That must be fun to calibrate.
It sure is. That is the auto heading card for vectored thrusters. It is all analog PID with lots of gain and offsets controls on the amplifiers.
I’d rather be known as the high cost guy instead of the cheap guy . Connectors matter a lot in my business and my minimum requirements are 1) multi-point contact between the pin and socket, 2) gold plated contacts (particularly for power connectors where resistance matters) and 3) positive locking. The Molex Ditto has the positive lock but it looks like neither of the other 2 items on my list. It does has wires already attached which is nice if they’re long enough for your application. But the extra buck for the DB9 is worth it in my book if you can afford the crimp tool.
@ Gene - The Ditto, connectors are supposed to have a clip at the back which keep the connectors from backing out. I’m hoping that this piece when it is available will make for a better solution. I would love to use those fancy DB9 connectors though. Is it that the DB9 connector in general is vibration resistant, or are those Datamate connectors vibration resistant?
@ Mr. John Smith - The Datamate connectors are specifically designed for and have been tested in high vibration environments. The whole DB connector family has been around for a long time and has proven to be a very reliable connector in a wide range of applications The crimp style that I use (and recommend) is also available in a full Mil-Spec version (just in case you have a bucket load of cash laying around) and I’m guessing the Mil-Spec version has been tested to some level of shock and vib. The good news is that I don’t think there is any significant functional or performance difference between a high quality, reasonably affordable DB connector and the full Mil-Spec versions.
Can you describe your environmental conditions, particularly shock and vibration?
@ Gene - During normal operation, there won’t be much in the way of high vibration or shocks. It will be pretty standard CNC milling and 3D Printing. The design of the machine is susceptible to shocks. I have not calculated what the max G would be, however you can get an idea by imagining that 15Kgs of the machine can free fall about 24 inches and come to an abrupt stop. I expect that the machine will continue to function after such a shock; connectors and all. There will also be sawdust, some heat, chemical fumes, water splashes, cutting oils etc. Conformal coats (@ Brett ) will keep out the dust and some static from the dust, so I’m not worried about IP67 capabilities of the connectors.
EDIT: Oh, also there can be high vibration if an end mill breaks and unbalances the spindle. But that is a fringe case that I’m not really planning for at this time, since the accelerometers on the effector should warn the SCADA that a shutdown due to malfunction is required.
@ Mr. John Smith - That helps a lot. There are a bunch of commercial and military specs for equipment that has to survive a drop from 1 meter onto a hard surface like concrete which equates to something like a 50g shock. Vibration is more complex to characterize but you should be able to find appropriate specs for a CNC machine. It is probably a good idea to find some ISO, IEC, DIN or whatever standards that apply to your environment and make sure your connectors (and everything else) meet those specs. Anyway given your environment, I’d think that scrimping on connectors might be the wrong place to save money. Standard DB connectors are always almost alway a good choice but pretty old technology in that they are pretty big. Most DB9s are designed for signal level voltage and current but there are high power versions. The Harwin’s connectors I mentioned are a much more recent design, much smaller and have different families for power applicatons and signal applications as well as hybrids where you can mix signal and power in the same package. Here are the environmental specs for the Harwin’s
Operating Temperature -55°C to +125°C
Humidity Classification 56 days at 95% RH
Vibration (with latches) 10-2,000Hz, 0.75mm, 98m/s² (10G), 6 hours total
Shock (with latches) 981m/s² (100G) for 6ms
Outgassing Product range includes a variety of plastics - please check the Outgassing page
If you google DB9 connector shock spec you’ll see they’re in the 50G range.
There are several other vendors with connectors similar to the Harwins, I just settled on those for a variety of reasons specific to my needs.
Good luck and let us know what you decide.
You didn’t say specifically, but Molex’s Micro-Fit 3.0 range has both wire-to-wire and wire-to-board, they’re fairly cheaply available, and you can get a good-enough crimper for $25ish and a quite-good crimper for $50ish.
Well, it seems like the Ditto connectors are not shorting as easily as the previous ones; even when they are half way seated. Time to rewire all the power connectors for the robot. :-[