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Triple Head CNC Install: Cape Town

Tool length issue experienced on a triple head CNC, and resolution.

In the last week I flew down to Cape Town to resolve a couple of issues on a 1325 triple head CNC. 

This machine is different to our other CNCs in that it has three spindles instead of one, and allows the user to perform multiple processes using different bits in the same job, without having to change tools. This speeds up production. This is the first machine of its type that we've sold, and the controller, while being really nice to use, was also totally foreign to us. It's a Weihong NK105 G2, pretty different from our usual RichAuto units.

When we had the machine, the assumption was that one uses the tool height sensor probe on all three tools, and off you go. We had only used this feature a couple of times and it worked, but we had set tools to protrude at the same length on the spindles, so we had not experienced problems with code that switched from one tool to another.

At the client, we encountered the problem that he had tools of different lengths as the bits were vastly different, and it didn't make sense that using the tool height sensor that he was experiencing tool height inaccuracies. On my arrival, we sent videos to our supplier in China, trying the tool sensor method, with an entire day of back and forth, and they were as stumped as we were.

We searched every possible menu function, changed any possibly related setting, tried again, and we were all stumped. Our CNC supplier sent us code assuring us it would work, and the heights were totally off when we ran the code. Tool 1 was right, tool 2 was 7mm too deep, and tool 3 didn't even touch the material. We swore more than a little at this point.

The supplier then suggested changing the Z-axis limit switch, which we did, and then came out with "your machine needs a software upgrade", which we would have to wait til the next day to get from the controller supplier. We carried on trying, and then the X-axis stopped working, with the driver giving a 007 error. At this point, at 6:30pm, us and our supplier in China called it a day and decided to revisit the issue the next morning.

The next morning Nicholas was at the client bright and early, and resolved the X-axis issue beautifully, which turned out to be a faulty connection created in transit. The supplier was ready for us as well, having spoken to the controller people while we were still sleeping.

Turned out tool length settings are a totally seperate setting from Z height zero. All we had to do was bring the various tools to the material surface, and press shift + 6, which opens up a "measure page menu", select "manual setting", press OK, and the controller prompts "Set tool length?", and press OK. Repeat for the other tools, and then bring the first tool back to the material, and set Z=0. Then you set your XY starting point, and you're ready to run code.

This measure page menu is something that is not in the Weihong manuals we have, and it seems not even our CNC supplier knew about it. 

The attached video shows us running code that runs all three tools, and all tools had to cut 1mm deep. After doing all the above the code ran successfully, and you can hear me cheering when the all tools were cutting at the correct depth, which was totally different from the previous day.

Moral of the story: you can give so much info to the supplier remotely, but if it's a new product, they might not even know how to resolve an issue and will need time to get info to convey to you.

Also, be patient with suppliers and give as much info as possible, because they don't always understand us right away, but it's ok to push them. 

In the end we got the machine to work correctly, learnt something new, and we have a happy customer.

Well done to Nicholas and David for working hard to help getting this resolved.


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