Difference between C7 and C5 ballscrew

The 200mm Coil Winding Machine is a low cost solution for people wanting to wind all different kinds of coils.

You only have to look at the price of commercial desktop machines that do not have the features of our software and the huge price difference. While designing the machine we have always thought of cost and tried to save our customers money, as well as still providing an accurate machine and keeping it as solid as we can.

But also we realise that more and more customers want the extras that you will find on commercial machines, such as higher torque motors, tensioners, spool holder cones, different nozzles etc and we try our best to source these and find the best way to implement them around our existing machine design so previous customers can upgrade their machine if they wish to.
This also goes for the controller and software/firmware with regular releases that are used on new machines, but also upgrades offered to existing machines.

So here we are now with our next upgrade option of ballscrew and rails.

Please see more information below.

C7 Ballscrew and linear round rails

As standard we supply our low cost 200mm Coil Winding Machine with a C7 ballscrew.
These are really nice rolled threads with near zero backlash over the short travel distance of 200mm.

Repeatability along the 200mm length with a combination of C7 grade ballscrew and linear round rails, in increments of 0.1mm is 75% or more per ballscrew turn, based on a 4mm pitch.

Rolled C7 ballscrew maximum lead deviation 0.050 over 300 mm
Ground C5 ballscrew maximum lead deviation 0.018mm over 300 mm

This is more than good enough for most coils being wound with the wire side by side.

But now because our software allows complete control of positioning of both bobbin motor and feeder assembly, we are getting more and more customers who want to use it for more complicated windings and very small wire with a variable pitch along the length of the winding.
A good example of needing this requirement is for people using the Absolute Scripting engine with thousands of small movements and winding coils such as LVDT but not generally needed for typical coils.

C5 Ballscrew and low profile rails

This is where the C5 ground ballscrew comes into play and also using low profile rails but the price increases and hence why we have never offered this as an option before.
After doing a deal with a company who makes ground C5 ballscrews, we are now able to offer the C5 ballscrew and low profile rail upgrade kits available at an extra cost to bring repeatability up when using very small wire with very small movements.

The upgrade kit can be purchased by existing customers that have a 200mm Coil Winder and we will supply a complete, assembled Axis that has C5 ballscrew, C5 support bearings, low profile rails, custom milled plates, profile and adapter plates so you can mount your existing wire guide.

Below we can see a picture of a test using a C7 ballscrew compared to a C5 ballscrew using really small wire of 0.05mm (0.0019 inch) and winding at a pitch of 0.1mm (0.0039 inch). So we should end up with a gap of 0.05mm between each winding.
Remember to allow for difference in wire thickness also as it is never the same as the wire size due to the coating and can vary long the whole length of a spool.

Right Click the picture below and choose open in new tab for a larger view.

Another interesting thing is that we wound these without a tensioner and just used the standard felt pads.
You can see this at the bottom of the coil wound with the C5 ballscrew at the bottom of the picture below.
If we had used a tensioner and the correct tension, these kinks would of been removed.

Here is a example of a secondary winding on a LVDT coil done with the C5 Ballscrew and low profile rails.
It has 18 segments using 0.05mm wire. Each segment has a set pitch which increases across each segment.

For new customers buying a machine we will be offering the C5 Ballscrew and low profile rails as a option which will be fitted to their machine before despatch.

For existing customers we will be offering a assembled kit as a upgrade option.

Below shows the C5 Ballscrew fitted with C5 support bearings.

The low profile rails give a much more rigid slide for the feeder carriage.

We supply the whole assembly already aligned and ready to go for existing customers that want to upgrad