[Danny_guy]

Hello everyone,

first of all, I apologize if a similar topic already exists. I looked for anything resembling my question to the best of my ability, but could not find anything.

As far as I understand, what I am trying to do is not a traditional solution. So much so, that I'm not even sure how the actual machining process is called in English. I think it is referred to as planing (when machining a flat surface) or shaping (when machining various grooves). A tool, somewhat similar to a turning (lathe) tool, is dragged along the surface of a workpiece in a linear motion, removing material as it goes along. The tool does not spin. It just cuts the the steel. A sort of straight line version of turning if you will. Shaving some material off of the surface, a couple of millimeters with every pass. Alternatively, the tool remains stationary and the workpiece moves. They used to do this to form large planes, as well as various grooves in flat surfaces. This process used to be commonplace a long time ago, but it has since been replaced by milling. I hope my attempt at describing this operation is sufficiently clear. If not, let me know and I will do my best to clarify.

What I'm trying to do, is to use a traditional, modern cnc mill to perform the operation described above, to cut some (relatively) tiny, but long grooves into a steel plate. I have already found some old theory books with speed and feed recommendations and other tips. I know the forces that would act on the spindle and I'm sure it will not do any damage to the machine. Also, I found the required tools and adapters to do the job. Just one problem remains to be solved, and I'm hoping someone here might have done something similar, or will have some ideas.

The tool to be used is going to be either a regular turning tool or a parting tool with removable inserts (fitted into the spindle via an adapter). For this to work, the tool (and thus, the spindle) has to remain static, in other words- it does not turn during the actual machining phase. The horizontal feed is the motion that cuts. Also, and this is the tricky bit, the tool must always be facing precisely forward, so as to make a proper cut. If the tool is misaligned, i.e. facing slightly sideways, the groove will be cut asymmetrically and, probably, otherwise flawed, not to mention the wear of the tool. I should probably mention at this point that this would not be a one-time-only experiment. It would be done repeatedly, over a small sized production run.

I guess what I'm trying to find out is if such a thing is at all doable? Has anyone ever tried such a thing? I imagine that the tool could be aligned manually the first time round, but it would be too time consuming to align it manually every time the operation needs to be carried out. Is it even possible to align the tool sufficiently accurately by hand? I think not.

I realize there are other options, but this is an interesting solution that has the potential to save considerable amounts of time, when machining long, thin, straight, repeating grooves.

[pippin88]

Bolt the tool to the side of the head rather than holding it in the spindle.

Not sure that a milling head is really designed for the loading like a shaper or planer.

[Danny_guy]

Thank you for your insight. I have seen some videos on youtube of a similar setup. However, the mill we have is rather large, and the groves to be machined are tiny, so the forces generated will not exceed those generated during regular milling with large end mills. The problem with this approach is that the tool would have to be inserted manually every time and removed after the operation so as not to get in the way during regular milling operations. This is not as good as just grabbing the tool from the magazine in terms of time efficiency. However, I suppose, it could be possible to come up with a sufficiently quick method of doing this. I will look into it further. Thank you.

[underthetire]

Problem will be holding spindle orientation. You would need some kind of mechanical lock, otherwise you could push the orientation off the M19 and some machines will alarm out, others will try to find orientation again by rotating the spindle. Maybe do something similar to an external through coolant adapter.

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[wizard]

Thank you for your insight. I have seen some videos on youtube of a similar setup. However, the mill we have is rather large, and the groves to be machined are tiny, so the forces generated will not exceed those generated during regular milling with large end mills.

You have a number of options to achieve this. You could try horizontal milling for example or make use of an air or hydraulic slide. Or you could make use of a servo based slide assembly.

The problem with this approach is that the tool would have to be inserted manually every time and removed after the operation so as not to get in the way during regular milling operations.

This is where a slide mounted on the side of the milling machine head makes sense. Such a slide can withdraw the tool when other work needs to be done on the machine. Further a retractable slide means you don't need to build a clapper box of any sort. IF the grove is as light as you are saying then you will likely be able to get buy with a fairly light slide assembly.

This is not as good as just grabbing the tool from the magazine in terms of time efficiency. However, I suppose, it could be possible to come up with a sufficiently quick method of doing this. I will look into it further. Thank you.

I don't think you want to go the CNC taper route here. It might work if you have an indexable spindle with good holding power but I'm going to assume the spindle doesn't offer that capability. Even if it did you would still need a way to orient the tool in the spindle correctly every time.


By the way Planners where as you describe machines with moving tables that pushed the part through tooling not unlike lathe tooling. The machines that pushed the tool back and forth where (are) called shapers. Planner could be massive machines, the direct descendants of this mahcies being Planner mills. I remember working on an old Planner Mill with four heads that was massive. You could walk around inside the control panel, a panel by the way that had a massive amount of TUBES to power those motors.

[Danny_guy]

Wizard, thank you very much for your informative response and for enlightening me about planers and shapers.

As a matter of fact, our mill does happen to have spindle indexing capability. I have some ideas about getting the tool oriented sufficiently quickly and relatively accurately. I will post an update on how this went and if it's worth the effort in a few weeks time.