how to make a quality crimped joint
A friend of mine was once advised by an employee in a car.
The Fi shop holds the curl to the cable with insulating tape and anything else. . . . . . .
Curling is a technology that enables the production of reliable, durable joints efficiently and easily with minimal training.
There are all kinds of criminals on the market.
The industrial users of Crimps can get information from the curling edge and tool manufacturers very well, so I will not delve into these applications in depth.
Instead, in this note, I would like to give some advice on the use of crimps, which you may encounter in installing accessories or repairing a car, boat or RV or home project.
Most of the content of this manual will focus on materials and tools, so I will discuss this in detail in three main areas and keep the introduction materials simple: high quality curled terminals for materials suitable for applications with known specifications (not solid core)
According to your application, in order to adapt to the terminal of the wire, you can choose or do not choose the wire to use.
First of all, do not use solid core wires, avoid using \"pipe wires\" if you want reliable work \"(
Several larger lines used to bury the trunk line in the pipeline).
Reliable use of this type of wire requires a specific type of crimp.
The best wire to use in general will be a multi-strand wire.
Then determine the wire size-
This may be listed in a number of ways, most often the ad hoc working group (
US line Rules)(e. g. 16AWG)
The cross-sectional area is square mm (e. g. 1sqmm)
Or the number of shares (e. g. 32/0. 2).
There are a lot of tables around to help you convert between common sizes.
If new wires are purchased, the dimensions are listed on the reel or package.
It may be more difficult to determine if an existing installation is modified.
Many wires are now either printed out or molded into insulation and this information is repeated along the length, so see if you can find it.
If you can\'t find this information, you have to go back to measurements and calculations.
Bring the insulation length back, then count the number of individual wires, and measure the diameter of one wire with a kilogramme or a cursor clamp.
You can then refer to the table, or calculate the cross-sectional area by multiplying the number of shares by the area of a strand calculated by π r2.
The insulation diameter is very important for the most reliable curl, as it affects how the rear part of the curl catches the wire, but as long as you use the standard wire, then this should not give you an important question.
However, it is important to consider that this is what you use in professional applications.
Now you know what wire size you have and you also need to figure out what you need to connect.
There are a lot of changes in curl, but there are some very common changes, most of which are shown in the image.
Crimp designed to fit threaded fasteners can be simply specified by Bolt size (e. g M4/ ¼”).
Other names that may depend on the industry and the manufacturer (
Such as Lu Carl, faston, \"blade \").
The key to getting a good joint is the quality of the curl --
It is difficult to get a good, long lasting joint with the curly terminals with poor quality.
For other technical reasons, the plating terminals offer a variety of different plating options to provide corrosion protection (
(Such as low contact resistance).
I will avoid any curl (
No plating so you don\'t have to re-plating
Visit it in the future and clean up its corrosion.
This is especially important in a more corrosive atmosphere, just like the atmosphere found on board.
The most common plating is tin, which will suit most needs.
Silver and gold are also common in some applications, but are usually used for low current/signal applications that require a minimum resistance on the joint.
The connector with better quality of insulation terminals has a metal sleeve to secure wire insulation, which is not available for lower quality components.
The image of the segmented Curl shown makes this obvious, but to determine this when not segmented, look down the curled barrel from the wire inlet end.
In a high quality part, you will see that the metal is almost close to the end of the curl, but in a cheaper part, it will stop the shortage.
All terminals will be sold in the defined wire size range-
This should be listed on the packet, but if not, and you are using pre-
You can judge the insulating part by the color of the sleeve.
The standard generally used is: Red insulation 0. 5-1. 5mm2 / 22-
16 AWGBlue insulation 1. 5-2. 5mm2 / 16-
Insulation material AWGYellow 4. 0-6. 0mm2 / 12-
There are other colors around, but unless you work in industry, aerospace or military, you are unlikely to encounter them.
These parts are made in one of two ways.
Piece or tube end.
The formed sheet is made by cutting the material from the plate and then shaping it at one end into a tube.
The better quality of this type will have thicker material and welded seams.
The end of the tube is made by cutting a piece of pipe into length, flattening one end and punching holes.
Tube type is often heavier work, so it is more common in larger sizes-
For example, you may encounter these problems on starting the motor feed. Open Barrel Un-
Insulation curl this type of Curl has changed the most so far, leaning towards the type used in the connector housing.
Of the thousands of available blades, the most common ones you may encounter so far are blade types, of which 1/8 are the most common (3. 2mm)and 3/16” (4. 8mm)
Also often encountered.
You will find that these connectors are widely used in automobiles, household appliances, Hi-
You will most likely find different types of other apps in your car-
If you need to replace these good automatic
Electrical suppliers can usually provide you with parts kits.
These types usually require a very special tool in order to curl properly.
These are the most common military ones.
Specifications connectors, but may also be available in industrial connectors, RF connectors and high quality D-Types.
They are made by turning the parts from the bar, so they are almost always round.
There are many other types of curls in other types, most of which have specific applications, so you are unlikely to encounter them in your daily life.
A large part of the packaging in the form of crimp can be automatically curled on professional machines --
It is usually a band or carrier provided on the reel.
These can be curled with hand tools, but need to be removed or cut from the carrier tape.
Other terminals are provided as \"loose parts-
A single part usually provided with a bag or box.
Like any other tool, choose a tool with a wide range of options covering a huge range of prices and quality.
A cheap universal tool may start at £ 2, the quality is good, the calibrated manual tool usually exceeds £ 400, and the automation equipment reaches tens of thousands or more.
In general, I will try to avoid any tool that does not have a ratchet function --
While sometimes this is not possible, it is better to know why to make a choice.
There are very few ways for pliers type tools to ensure proper integration of curl
There will be a ratchet tool.
Therefore, you can guarantee that the curl is formed correctly (
If you choose the right curl and wire for the mold).
Similarly, there is the same problem with hammer type tools.
There will be more information later.
In order to get the best results, tools suitable for the terminal should be selected
The best way to do this is to buy the tool recommended by the manufacturer for every curl you use, but for obvious reasons this is not very practical for DIYer.
The manufacturer\'s data sheet usually lists the part number of the correct tool.
For the most common crimps, there are general tools that work well with reasonable prices.
In fact, the number of manufacturers of these tools in the world is very limited, so if you buy a cheap basic tool, it is likely to be the same part.
The main manufacturer of these products is a company called OPT in Taiwan --.
From personal experience, these are good functional tools for insulated terminals, blade terminals and non-insulated terminals
Insulated closed barrel terminal at reasonable price.
Other major manufacturers of manual tools for large curl suppliers I know are: these are all sold in their own name and also for others \"badge works \".
However, you have to go to the dealer/dealer to buy their parts as they are all sold to the industry only.
If you\'re using un-
Insulation curl, need to hold it, put a suitable sleeve on the wire.
Usually the shrinkage ratio of 3:1, the Heat shrinkage of the adhesive lining will ensure that both the wire and the curl have good support.
The length is at least 2 times that of the curling barrel and usually gives a good grip.
Other sleeves can be used
In particular, the sleeves of neoprene (
Herman sleeve)also work well.
Before doing a lot of curl, it may be worth a test curl on representative wires and terminals to make sure your settings are correct.
Once you have determined the length of the wire, peel off the end and be careful not to damage the conductor.
It is possible to indicate the length to be stripped on the curled package, but if not, it should be 1-when the wire is inserted into the curl-
Stretch out 2mm from it.
Insert the wire into the curling edge to make sure that all the wires are there and that no wires will deviate.
It is not recommended to twist the shares together.
Carefully put the curl in the wire into the tool (
You may find it easier to put the curl into the tool before having some curly wires)
And make sure the wires are at home. Cycle the tool-
If it is a ratchet tool until the tool is released.
Remove and check the sides-
Make sure the wires are in the right position and successfully grab the insulation.
Give a small tugboat to make sure it is completely curled.
If you are using some cheaper/No.
Ratchet tool, you may need to curl each terminal twice and there may be two settings on the tool.
If you need to do so, first curl the curled conductor end and then the insulation.
If the Heat Shrink tube or other casing is used.
Install the sleeve and heat it to narrow down if needed.
Use the right heat source-
Ideally, a hot air gun can be used, but items such as soldering iron can be used with great care.
Before shrinking, make sure the casing is in the right position and do not get in the way of the curled end.
More information some science and quality control, can curl and curl on the terminal;
The curl system is designed to compact the wire set to a set level so that there is no gap space (gaps)
Left between stocks.
This will prevent moisture and oxygen from entering the curl, thus preventing corrosion from happening.
If this operation is performed correctly, the rear part of the welding curl (
Some people will recommend it)
It will not have any effect on the corrosion resistance of the joint, because there is no space for the solder joint to enter.
Ultimately, the curl process is designed to deform the wire and curl it to the preset level to eliminate the space and cold process the wire to the pre-
The level of determination. Under-
Curl can be achieved by using the wrong tool or mold instead of looping the tool to a fully closed tool, using a pliers type tool, or by incorrect curl and wire selection, these gaps will be opened to allow moisture and oxygen to enter, eventually allowing corrosion, resulting in a high resistance joint or mechanical failure. If under-
After curling, the mechanical strength of the joint will also be reduced, and at extreme levels, it will be pulled out with a very low force.
Although the tension of the joint is not an ideal test (due to over-
The blank holder problem described next)
, This is a common test that is applied quickly in a factory environment, so it is usually used as a quality control check.
Excessive compression of the joint can also cause catastrophic consequences
In extreme cases, the stress applied on the wire may result in a complete failure, which may be obvious.
A less obvious problem is that the sensitivity to fatigue is higher, which will occur in the place of vibration, and the failure may not be obvious for a period of time.
This type of failure is similar to what happens when you keep bending the paper clip
The material worked hard and eventually failed.
Excessive curl is more difficult to detect, as simple pull tests do not necessarily solve problems due to the tendency to use other quality control techniques, although these are not practical for diers;
This is a destructive test and is the only fully determined way to determine the quality of the curl
Therefore, it is often used in industry to ensure that the design/calibration and setting of the curling machine is correct, where sampling and analysis can be made.
The process involves cutting the curl joint through the curl area, mounting and polishing the cross section, and checking and measuring with a microscope.
The criteria for good union are mainly to determine whether the correct merger has occurred --i.
E there is no void space, there is no inclusion of foreign matter or oxide, and there is no approximate hexagonal part of the winding wire strands. Pull tests-
By hand, this can be a gentle tug-of-war on the joints, but in the production environment, the calibrated tester is usually used to apply force until the joints fail and notice the yield force reached.
It could be a quick one.
Insufficient process check will be detected
But not necessarily excessive. crimping. Crimp height-
Measuring the height of the terminated wire in the Curl area is a good way of quality control because it is not
Destructive and can be simply picked up under the edge of the roll and the edge of the roll. Crimp force-
Many automated curling tools measure the force applied during curling.
This is another reliable way to obtain the quality indication of the curl, and its advantage is that it is an ongoing inspection
No need to stop the machine or remove the sample. Soldering-
You may see suggestions for welding crimps elsewhere.
There is no need to weld any curl at all.
In fact, doing so may reduce the reliability of the curl.
Crimps is designed to control the bending of the cable at the entry point.
Welding will harden the joint and cause premature failure. Esoteric tools-
Due to excessive danger
The curl as mentioned above and the difficulty of detecting it, I strongly recommend not to use tools of hammer type or anything that is not specifically designed for curl type.
This includes squeezing with a vise, squeezing with a nail to indent, using ground pliers, and banging the vise with a hammer or any other cruel method that might come to mind.
You may get a reasonable result, but the risk you won\'t have is very high and the Federation fails prematurely.
Unfortunately, there is very little extensive information to read further about Curl technology, and by far the best books are out of print;
Manual of electrical connectors: Technology and Application (
Electronic Packaging and interconnect series)
Robert S Mroczkowski, ISBN 978-
0070414013 most major curling manufacturers, however, produce some sort of guide, and here are good examples.
Other services are available;
Finally, my best suggestion for a curled joint with reliable sound is;