Wire Cutter/Stripper

Projects General Guidance
1

Hello

I am planning on designing an automatic wire cutter and stripper. Its intended purpose is to cut the wire to a specified length and strip a specified length as well.

From what I have read the best way to feed the wire for a specified length is using a stepper motor. I dont understand mechanically how the stepper motor will feed the wire though. Do I need to attach a roller to the shaft. Where would I buy a roller from? Also would I be able to control a series of rollers using one stepper motor.

Secondly for the cutting mechanism, I plan on using a servo motor to move the blade up and down.

Lastly, for the wire stripping I have not put much thought on how I would do this but I assume you would rotate a blade around the wire

Please advise how I would feed the wire and any other suggestions for cutting and stripping are appreciated.

Note: The wire will be roughly between 20-30 AWG and will be feed from a spool.

Thanks

2

What gauge of wire?
What insulation type an its thickness?
How long are the segments going to bee?

I have used a machine based on this idea, not sure how it actually worked.
Maybe this will give you some ideas.

Two2.jpg
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http://forum.arduino.cc/index.php?topic=353064.msg2433928#main_content_section

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3

yuknowhoitiz:
From what I have read the best way to feed the wire for a specified length is using a stepper motor. I dont understand mechanically how the stepper motor will feed the wire though. Do I need to attach a roller to the shaft. Where would I buy a roller from? Also would I be able to control a series of rollers using one stepper motor.

Secondly for the cutting mechanism, I plan on using a servo motor to move the blade up and down.

Lastly, for the wire stripping I have not put much thought on how I would do this but I assume you would rotate a blade around the wire

I reckon you need to put more thought into it and sort out all these mechanical issues before coming here for help with your programming.

The sort of thing you want to do is by no means simple.

...R

4

I'd look at 3D printer extruders for your wire feed system. They do exactly what you're needing and 3D printers have become so popular that the parts are very cheap.

As for stripping, I use one of this type of wire strippers:
www.ebay.com/itm/111818704719
that sort of mechanism seems like it would be easy to incorporate into a machine. No rotating blade necessary, just extrude the wire between the jaws then use some mechanism to close the handles and release

5

pert:
I'd look at 3D printer extruders for your wire feed system.

? ? ?

Melt the wire and extrude it ?

...R

6

The typical 3D printer is going to mangle the insulation on the wire. They have teeth that bite into the plastic.

I'd be looking at a steel wheel running on a rubber idler. Or maybe rubber both sides. I'm sure if you pull apart a laser printer or copier you will find appropriate parts. You will also get the stepper(s), stepper drivers and lots of mechanical parts too.

Go to your local dump and look for a large copier or printer. They will probably let you haul it away for free but charge you when you bring the carcass back.

7

Robin2:
Melt the wire and extrude it ?

On a 3D printer the extruder is the part with a stepper fitted with toothed rollers that precisely feeds the filament to the hot end, which is the part that melts the filament. I also find that term a bit strange but it is the standard terminology used in that industry.

8

pert:
On a 3D printer the extruder ...

I know generally how they work. I just assumed the term "extruder" mainly referred to the melting part. Some of them have the feed mechanism at some distance from the hot end,

...R

9

Robin2:
Some of them have the feed mechanism at some distance from the hot end,

That feed mechanism is a specific type of extruder called a "Bowden Extruder" because it pushes the filament through a tube (as in a bowden cable) to the hot end. That allows the extruder to be mounted to the frame, rather than the moving part of the printer.

MorganS:
The typical 3D printer is going to mangle the insulation on the wire. They have teeth that bite into the plastic.

I still think it's worth looking into. The sharp parts of the teeth could easily be sanded down or coated with something like plasti-dip. You can adjust the tension on the extruder. For this application the extruder shouldn't need to provide anywhere near the amount of force required to push filament through the nozzle on a hot end so you don't have to set it so tight as to bite into the insulation. It's quite possible I'm wrong though, I have absolutely no 3D printer experience. I just read Hackaday so I end up absorbing some info on that subject whether I like it or not.

10

yuknowhoitiz:
Hello

I am planning on designing an automatic wire cutter and stripper. Its intended purpose is to cut the wire to a specified length and strip a specified length as well.

From what I have read the best way to feed the wire for a specified length is using a stepper motor. I dont understand mechanically how the stepper motor will feed the wire though. Do I need to attach a roller to the shaft. Where would I buy a roller from? Also would I be able to control a series of rollers using one stepper motor.

Secondly for the cutting mechanism, I plan on using a servo motor to move the blade up and down.

Lastly, for the wire stripping I have not put much thought on how I would do this but I assume you would rotate a blade around the wire

Please advise how I would feed the wire and any other suggestions for cutting and stripping are appreciated.

Note: The wire will be roughly between 20-30 AWG and will be feed from a spool.

Thanks

My suggestion is to split the two operations, since you seem to have no machine shop capability.

Let me describe the wire measuring and cutting machine I purchased years ago on Ebay. It does, indeed have a stepper motor and a microcontroller. A keypad is used to enter then length of the cut wire.

There are two fairly hard rubber tired wheels that pull the wire through the machine. Both are fairly hard rubber. One wheel is on the stepper shaft the other is spring loaded to pinch the wire against the stepper motor wheel.

The wire proceeds from the wheels through a guide hole and to the cutting station. The cutter is a solenoid driven blade that actually makes the cut. The solenoid is powered by a large capacitor with a fairly high voltage. Don't recall how high. That gives a very quick and powerful cut to the wire. If you use another stepper to drive a cutter, you will have to stop the wire feed while it is being cut.

I have had to replace the original pinching wheel because the rubber tire wore out. I turned a new wheel out of hard rubber using a lathe. Close size was good enough because it was not a measuring wheel.

There are two types of insulation stripping. One leaves the insulation on the wire, the other pulls it completely off. My strippers are air driven with a foot switch. The position of the insulation cut and how far to pull the insulation are both hand adjustable. I think the actual insulation cutting is done by a blade made of multiple very fine, sharpened wires. They go through insulation, but not the wire.

Paul

11

Feeding ought be pretty similar to feeding a filament to a 3D printer, so look at some of the
designs for those - might be directly usable, though they tend to be for a fixed diameter of filament.

Cutting needs shear-action, you could probably adapt some existing cutting tool - the force required
may be quite large for a hobby servo, some sort of linear actuator sounds more plausible.

Stripping the wire is going to be tricky, normally you need a tool preset for the wire diameter that
doesn't quite cut through the insulation, then pulls it to snap off without scratching the conductor(s)

Suggest buying a hand wire-stripper to study the mechanism (and maybe cannibalize it)

12

You need lot of mechanical parts to build the same, it actually consist of two stepper motor one is feeder and another is cutter( only for length cutting
For striping you need 3 stepper.
See some videos online.

13

Here's my idea for using a readily available stepper based 3D printer extruder for the wire feed put into action:

MorganS:
The typical 3D printer is going to mangle the insulation on the wire. They have teeth that bite into the plastic.

From the comments on the video:

@download333
Does the drive gear hurt the insulation at all?

@Must Love Science
Not at all. The tension of the drive gear can be adjusted to where it is gripping lightly but can still pull the wire though. No visible markings can be seen on the insulation from the drive gear.

That's using an unmodified extruder. It may be that some insulation types are more delicate than others but this is certainly a proof of concept.

14

Feeding & Cutting is easy.
Stripping is much more complicated. Either a rotary blade, or reversible feed path.

Enjoy this.
Simplest wire cutter on a budget!

15

lastchancename:
Simplest wire cutter on a budget!

I think the one in the video I posted would qualify as significantly more "simplest" than that one, especially if you skipped the unnecessary LCD. I think the system of actuating the cutter used in your video would probably cost less $/force than the servo but certainly more work to set up and code.

I don't see why you couldn't just add on this sort of wire stripper:

with the same actuator system as the cutter.

16

Pulling any wire off a 100 ft. spool is a lot harder than people seem to realize.

Paul

17

...particulaly when it is time to stop!

18

I'd think if an extruder can handle a 1 kg filament spool while forcing the filament through the hot end it should be able to do a 100ft roll of wire but certainly the spool holders used in both the videos are not ideal. If the extruder has to strain against the spool then you will need to set the tension higher to avoid slippage, which will increase the likelihood of damaging the insulation. I think there are motorized filament feeders for 3D printers that turn the spool but I'd start with a wire spool holder that minimizes friction to see if that's good enough.