An old Roland MDX-15 mill to revive

Some 14 years ago, I have purchased a Roland MDX-15 indenting to use it for my various projects to fabricate custom part and for sculpting. I did use it for a while with various degrees of success but had eventually gave it up. It has too many limitations out of the box.

I am mostly bothered by the buggy electronic board. The manufacturer, Roland DGA choose to equip it with a hardware that does not support any set or subset of commands in the standard G Code definitions for CNC machines. Instead, they created their own set of command called RML-1 to use with their milling machines including MDX-15.

That would not be a big issue for me, as the package contained also a set of drivers and Windows applications to assist in converting a 3D model created with an independent other application into the set of commands to execute cutting out a form on a physical block.

Over the years, I have tried cutting out models from wood (soft or hard), and wax. Often though the mill would have just randomly jerk causing the mill bit to break. Thus, I ended up buying and ruining tens of such mill bits. Any of those 1 mm bits costed me $20, so I was not happy at all seeing them ruined after 4-5 hours of happy milling out the model.

Eventually, I deposited the mill in my basement where it sat for 10 years untouched.

Earlier this year, I started a project which required the making of a PCB board. I did design the circuitry, and than the PCB board itself. Then thinking it would be easy to make one at home with PCB kit, I started working on it. Still, the hurdle of drilling those many holes in the board at precise location which I remembered encountering in the past made me thing of reviving my old MDX-15.

Unfortunately, I have lost the CD containing the original Roland applications such as Modela, Dr. Picza etc. Besides, having upgraded my operating system a few times since 2008 :-) when I have purchased the mill, I have no other means to communicated with it but through the printer driver with the manufacturer provides on its website.

After cleaning it, and re-lubricating its moving parts, I thought the mill was ready to work. However, I spent (wasted) almost 2 weeks on writing a Java application to convert the G code based drilling file by the open source PCB design application into RML-1 commands. The result of that effort is available for those who want to try the same at

The results were somewhat positive in the end. After may struggles and without ruining any more drilling bits (I used one of 0.5 mm diameter), I managed to complete drilling a PCB having 150 holes. But the work was completed in 9 hours because of the issued with the board, all described as it follows.

Before starting the actually drilling using an expensive bit, I kept sending RML-1 instructions to the mill hoping to find the right combination which it can process. After tinkering with it for days, I eventually realized that the damn hardware cannot process more that 3 instruction in a row without stopping in failure. Even with no load at all, just instructing it to move the XY axis from origin, the mill will stop with one of the fatal errors described in its user guild. During the month long tinkering with the mill, sending it various combinations of commands, I was not able to make it process more that 3 move and drill at a time without getting an error fatal signal at the end. So, it needs to be powered off and re positioned at origin over and over again.

So, I had to break the work plan containing 150 drilling holes in 50 sets of 3 commands. The execution of which (with power off, and repositioning) took 9 hours in total. That is a lot. If I had used my drill manually, I would have competed that work in less than an hour. Not good.

The only up size of the Roland mill for drilling PCB is that the positioning ended up at pro-grade. If I had drilled manually, I would not have been able to obtain the same level of accuracy.

I conclusion, the mechanical parts of the mill are worth saving. But its electronics are buggy, and its manufacturer does not provide any support. If I knew of the issues the board actually has processing its own commands back 10 years ago, I would have insisted in getting a patch from Roland. At this time though, it is late. My only option is to replace the damn hardware.

This is my first blog posting about replacing the electronics on MDX-15.

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