Strengthen molex AKA style crimps/wires

Strengthen molex AKA style crimps/wires

Joined: October 1st, 2014, 8:46 pm

July 17th, 2017, 9:47 pm #1

I've started getting a lot of orders for chaos dm3 and alias boards.

I'm wanting to make some more PC cables so people with an old enough PC could still use it.

We went and used the aka pico blade molex across the "board". Yes, I intended the pun!

Also, I'm doing a lot of drone stuff and this connector is becoming pretty common.


My problem is the wires do not like to be moved much one they're crimped. You can put then in a static position and they'll stay forever. Put them in a high vibration or where they're being pulled in and out of the socket and they break like crazy.

I've been trying to find a way to strengthen this for years. Maybe I'm googling the wrong term, but others have to have this complaint.

Anyhow, I've tried super glue, hot glue, really soft aircraft rtv,epoxy, spit and bodily fluids and nothing has worked.

My brain tells me that the strain relief I'm trying isn't going to work if it's not connected to the housing because it will still let the wires flex at that point and add extra weight to the joint. There just isn't any extra meat on the connector housing to glue to.

I haven't found another style of housing that they offer. I haven't looked to see if anyone has been clever and 3d printed something.

I have guys wanting cables, but I'm not going to sell them unless I can keep them from breaking.

Any ideas


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Joined: October 28th, 2014, 1:06 am

July 17th, 2017, 10:00 pm #2

Is the wire itself breaking, the metal crimped connector, the plastic part of the connector? Can you send a photo of a break? When you tried the hot glue, how did you use it,(what was glued to what), and how exactly did it fail?

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Joined: April 18th, 2005, 4:54 pm

July 17th, 2017, 10:23 pm #3

I've started getting a lot of orders for chaos dm3 and alias boards.

I'm wanting to make some more PC cables so people with an old enough PC could still use it.

We went and used the aka pico blade molex across the "board". Yes, I intended the pun!

Also, I'm doing a lot of drone stuff and this connector is becoming pretty common.


My problem is the wires do not like to be moved much one they're crimped. You can put then in a static position and they'll stay forever. Put them in a high vibration or where they're being pulled in and out of the socket and they break like crazy.

I've been trying to find a way to strengthen this for years. Maybe I'm googling the wrong term, but others have to have this complaint.

Anyhow, I've tried super glue, hot glue, really soft aircraft rtv,epoxy, spit and bodily fluids and nothing has worked.

My brain tells me that the strain relief I'm trying isn't going to work if it's not connected to the housing because it will still let the wires flex at that point and add extra weight to the joint. There just isn't any extra meat on the connector housing to glue to.

I haven't found another style of housing that they offer. I haven't looked to see if anyone has been clever and 3d printed something.

I have guys wanting cables, but I'm not going to sell them unless I can keep them from breaking.

Any ideas

Just not wrapping my head around the application,so not 100% sure what the problem you're having is a result of.
The question really is where the break is occurring and which connector you're using.
An exact molex part number for both male and female sides would help.

-Hans



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Joined: October 1st, 2014, 8:46 pm

July 17th, 2017, 11:22 pm #4

The wires tend to break at the base of the crimp.

So the goal for me has been to create a solid connection between the housing the crimps snap into.


https://wiki.paparazziuav.org/w/images/ ... _crimp.jpg


So I'm trying to prevent the breaking wire from the crimp.

After much movement at all the wires just snap. They're a like 30ga? So there isn't much there to work with.
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Joined: September 12th, 2014, 3:32 am

July 17th, 2017, 11:25 pm #5

Just not wrapping my head around the application,so not 100% sure what the problem you're having is a result of.
The question really is where the break is occurring and which connector you're using.
An exact molex part number for both male and female sides would help.

-Hans


depending on the part #, there might be a insert/remove cycle limitation in play as well. Some connectors do not like being plugged and unplugged a lot.

(that's one reason why world+dog jumped ship from Mini-USB to Micro-USB- the connector is around the same size, but the insert/remove cycle count is twice as long. (5,000 on Mini vs 10,000 on Micro)

If it's the actual wire breaking, the first thing to to see if you are using stranded vs solid wire- solid doesn't like to flex at all. Stranded is much better at the expense of being more fiddly to crimp to a connector.
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Joined: September 12th, 2014, 3:32 am

July 17th, 2017, 11:27 pm #6

The wires tend to break at the base of the crimp.

So the goal for me has been to create a solid connection between the housing the crimps snap into.


https://wiki.paparazziuav.org/w/images/ ... _crimp.jpg


So I'm trying to prevent the breaking wire from the crimp.

After much movement at all the wires just snap. They're a like 30ga? So there isn't much there to work with.
Solid core wire (and mentioned in my other post) doesn't like to flex. Stranded works a lot better, but it's fiddly to work with especially at gauges that small.

Just my $0.02.
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Joined: October 8th, 2014, 2:05 pm

July 18th, 2017, 12:16 am #7

I've started getting a lot of orders for chaos dm3 and alias boards.

I'm wanting to make some more PC cables so people with an old enough PC could still use it.

We went and used the aka pico blade molex across the "board". Yes, I intended the pun!

Also, I'm doing a lot of drone stuff and this connector is becoming pretty common.


My problem is the wires do not like to be moved much one they're crimped. You can put then in a static position and they'll stay forever. Put them in a high vibration or where they're being pulled in and out of the socket and they break like crazy.

I've been trying to find a way to strengthen this for years. Maybe I'm googling the wrong term, but others have to have this complaint.

Anyhow, I've tried super glue, hot glue, really soft aircraft rtv,epoxy, spit and bodily fluids and nothing has worked.

My brain tells me that the strain relief I'm trying isn't going to work if it's not connected to the housing because it will still let the wires flex at that point and add extra weight to the joint. There just isn't any extra meat on the connector housing to glue to.

I haven't found another style of housing that they offer. I haven't looked to see if anyone has been clever and 3d printed something.

I have guys wanting cables, but I'm not going to sell them unless I can keep them from breaking.

Any ideas

The finer the pitch, the more breaks you'll encounter.

The best strain relief I've ever seen for crimped Molex-teminated cables is epoxy. It needs to attach to the connector body for that to work, otherwise all the wires break at once. Once you glom some epoxy on the back of a Molex plug, the wires are almost guaranteed to break elsewhere. (Although it is possible to contaminate the plug contacts with epoxy. Scrap it and start over if that happens.)

You'll never repair a cable stabilized with epoxy. Virtually all of the Molex connectors we use at work are only to allow quick assembly. Nobody expects to actually pull the connectors apart and attach new cables. (Except me, when I have to debug a board or assembly. I get away with it maybe 80% of the time.) If you're making a programming cable or something else that is intended to be connected and disconnected more than a dozen times, find a different connector.


If it ain't broke, I'll fix it!
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Joined: October 28th, 2014, 1:06 am

July 18th, 2017, 12:31 am #8

I've started getting a lot of orders for chaos dm3 and alias boards.

I'm wanting to make some more PC cables so people with an old enough PC could still use it.

We went and used the aka pico blade molex across the "board". Yes, I intended the pun!

Also, I'm doing a lot of drone stuff and this connector is becoming pretty common.


My problem is the wires do not like to be moved much one they're crimped. You can put then in a static position and they'll stay forever. Put them in a high vibration or where they're being pulled in and out of the socket and they break like crazy.

I've been trying to find a way to strengthen this for years. Maybe I'm googling the wrong term, but others have to have this complaint.

Anyhow, I've tried super glue, hot glue, really soft aircraft rtv,epoxy, spit and bodily fluids and nothing has worked.

My brain tells me that the strain relief I'm trying isn't going to work if it's not connected to the housing because it will still let the wires flex at that point and add extra weight to the joint. There just isn't any extra meat on the connector housing to glue to.

I haven't found another style of housing that they offer. I haven't looked to see if anyone has been clever and 3d printed something.

I have guys wanting cables, but I'm not going to sell them unless I can keep them from breaking.

Any ideas

The problem might be that you're nicking the wire when you're stripping it. Are you doing in manually? You might need to go with a thermal stripper which doesn't damage the wire.

Have you tried heat shrinking the wires after crimping?
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Joined: October 1st, 2014, 8:46 pm

July 18th, 2017, 4:12 am #9

Solid core wire (and mentioned in my other post) doesn't like to flex. Stranded works a lot better, but it's fiddly to work with especially at gauges that small.

Just my $0.02.
Nt
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Joined: October 1st, 2014, 8:46 pm

July 18th, 2017, 4:17 am #10

The problem might be that you're nicking the wire when you're stripping it. Are you doing in manually? You might need to go with a thermal stripper which doesn't damage the wire.

Have you tried heat shrinking the wires after crimping?
I'm using a normal hand held scissor style steeper. I'm not guaranteed that I'm not hitting a conductor here or there. If I notice I've done it, I start over again.



It is a problem with this style no matter who crimps it.

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