Manual bridgeport cnc conversion tool changing question

[Noobiecnc]

Total noob here. At work we got a new to us 12 x 30 bridgeport with a cnc automation cnc conversion. I'm new to machining entirely along with g code but I've been teaching myself and learning some stuff the expensive way like snapping off endmills and scrapping parts lol but that's the cost of education especially jumping into the fire like I like to.
I've done a few projects with varying levels of success but I really want to try a job with multiple tool changes next but I only have the tooling I've invested personally into this machine. So when I want to change a tool out I have to break down my one collet holder and insert a new tool.
Are there some good tricks for this that could maintain accuracy? When the machine runs for a tool change it just goes immediately back to machining after the new tool is inserted. I don't seem to have any sort of probing devices or any sort of z axis offset type of thing where the tool touches off electrically that I've seen on routers before.
I can set up all my tools in fusion 360 when im doing the programming and designing and seems like I could set the tools off my one collet holder to a reasonable accuracy but what if I wanted to switch out to other tooling besides my collect holder, like a drill chuck or a my face mill that has it's own r8 taper and a fixed hieght where I would loose the reference face i'd be measuring from

 

[EmGo]

I can set up all my tools in fusion 360 when im doing the programming and designing and seems like I could set the tools off my one collet holder to a reasonable accuracy but what if I wanted to switch out to other tooling besides my collect holder, like a drill chuck or a my face mill that has it's own r8 taper and a fixed hieght where I would loose the reference face i'd be measuring from

Tool presetter, except they've been outdated so long you won't find one. And even if you did, you're too cheap to buy it.

Turn up a female R8 socket with a flat bottom and use a height gage on a surface plate to measure length. Can substitute a piece of glass for the surface plate in a pinch. Diameters you can mostly do with a micrometer, except maybe boring bars and so on. You could make a fixture to measure those as well.

A few more R8 holders aren't that expensive, btw.

 

[Noobiecnc]

Tool presetter, except they've been outdated so long you won't find one. And even if you did, you're too cheap to buy it.

Turn up a female R8 socket with a flat bottom and use a height gage on a surface plate to measure length. Can substitute a piece of glass for the surface plate in a pinch. Diameters you can mostly do with a micrometer, except maybe boring bars and so on. You could make a fixture to measure those as well.

A few more R8 holders aren't that expensive, btw.

The female socket is a good idea! Basically getting to simulate the spindle in a measurable way. That's gonna be the next project
I invest in tooling when I can but the personal funds are pretty tight these days so when the funds are spent the thought process usually goes to what will take me farther vs what makes stuff easier for now, that'll change with time though. One of these days the boss will need something done and ill get a bunch of tooling but until then I'll get by with what I have

 

[Noobiecnc]

Should I be using tool offset information in the programming or should I be doing that at the controller when setting up for the job? Is it like defining part position and work offsets?

 

[Noobiecnc]

The tool height (z) are entered in the machine controller, as is the x,y zero position of the work. Usually, Tool #1 is the "zero" reference tool, so tool #1 should be set up at physical z0, the same z0 as is in the cam (usually the top work surface of the part). In the cam output, all the lines that have a z height, have nothing associated with them other than a tool #, so the control uses the entered tool-heights (note you have to make sure you get your +'s and -'s correct when entering the relative tool heights to the 0-tool (#1). Doesn't matter (at least in my system) what is entered for the tool radius in the control, as long as the actual tool diameter installed for the given tool# is the same as in the cam-data.


While there may be some way to do work around it, you really need to get some additional tool-holders. You didn't state what kind of r-8 collet tool-holders you are using. As an aside, an r-8 collet is not very desirable for tool-changing, having no real seating reference--just for starters. (I think Tormach and others sell an adapter system for quick-change tools in an r-8 spindle). Also, minimizing tool stickout on a light-duty machine like a bridgeport is desirable.

With the Interact 2 Bridgeport machine, I have a bunch of different kwikswitch 200 holders, most are accura-flex collet holders, and several drill-chucks. Note that the kwikswitch holder is designed for changing tools, it's a taper-locking gizmo (these spindles could be ordered with standard bridgeports, and you can find the spindle assemblies for Bridgeports on ebay at a reasonable price, of course the spindle must be removed to change them. There is also a kwick-switch to r-8 adapter (none on ebay at the moment but here's one for a nmtb taper https://www.ebay.com/itm/265543943464?hash=item3dd3a70528:g:inQAAOSwZ8FiBbUH; the possible issue with these is the additional tool stickout, since it's an adapter and not integral to the spindle) .

Don't know how your control software works, but for example in a TNC Heidenhain manual-change (fixed head) CNC, the program pauses and spindle stops whenever there is a tool change, you can then put the machine in "manual" mode and move it anywhere wanted by the handwheel to allow a tool change, then manually move the cutter back over the general machining area, put the machine back in "program run" mode, and resume machining.


The following describes how to set tool heights in the machine, without using a tool-presetter or other "off the machine" device such as height-gages and such.

Note Tool #1 is usually the Z0 tool in most software, all other tool heights are recorded and input relative to this tool length.
a) set tool# 1 at z0 on the z0 surface of the part (I use a .010 aluminum shim and subtract the .01 when entering 0 in the control)
b) touch-off the remainder of the tool #'s (corresponding to the CAM tool #'s) on the z0 part surface ( with a .010 shim and subtracting the .01 when entering in the control), and record the z-heights.
c)enter z-heights into the control's tool info table (must be careful with the correct +/- relative to the 0-tool); (in the machine control tool table it doesn't matter what tool diameters are entered, that is in the CAM data).

For all this to work, you need a holder where the tool stays fixed, and the holder has a decent consistent seating position in the spindle. An additional problem with using adapters/tool-holders in an R8 machine is the additional tool-stickout, and subsequent decrease in rigidity. But you need at least 3 or so holders of some sort.

I have one 3/8 solid holder with the set screw, and a er32 collet holder for the price, it seems pretty alright but I have noticed the rigidity issues resulting from the stickout/inexperience but seeing the tool slightly runout. I'm seeing the need for more holders lol sounds like a endless problem.
The control doesn't seem as user friendly as others. Thing is running windows 95 and only way I've gotten files to run is on floppy disks.. I have a better understanding of setting up the tool offsets
What about work offsets? I currently have to skip past the wo line to run anything. Seems like work offsets are some absolute position on the table itself instead of a defined position. First thing I do when powering the matching on is home it, coordinates go all 00s. All coordinates are based from home until until part position is defined at which point a little arrow symbol appears by the new zero which has overridden home zero to it can't be seen anymore. Go to work offset menu and enter g54 offset 00. Run simulation, coordinates look good, nothing appears crazy. Program runs the g54 offset line and the machine will override any defined input. Used to run into limit switches and put a stop to the whole show. Found in the settings though somebody had the table size set to 60in in all axis. Got that changed but I've just ignored the work offset since due to the issues with it. Especially have to redo the entire define part position every time it happened

 

[EmGo]

Should I be using tool offset information in the programming or should I be doing that at the controller when setting up for the job?

There isn't really any "should". Controls all seem to have different recommended methods and every shop seems to have its own preferred method. No matter what you do, if you go somewhere else it will be different. So may as well know upfront you'll have to be flexible. If you understand the principles, then the different approaches will all work fine.

I personally prefer to write the program for a specified tool length and diameter, then use the offsets to adjust for the difference between programmed and actual. I believe that's pretty common. But don't kid yourself that there's only one "correct" way. Choose the way that makes the most sense to you, then be willing to do it another way if you go somewhere else.

And I frequently use G92 and even sometimes relative positioning, which will excite the masses for sure, but oh well It's all just tools to achieve an end, the more methods you are comfortable with the easier it is.

 

[Noobiecnc]

I picked up a couple more tool holders for tool changes.
I don't understand how to connect my laptop to the rs232 port on the machine. I can send files from the laptop but I don't know where to access them from the machine. The windows 95 op system doesn't give me any list of places to pick from I just have to know the name of whatever im trying to access so I only know how to transfer files with floppy drives lol which limits the size of my program files anyway to 1.44mb. It does allow a perfect time while reloading part x of whatever program to readjust tool offsets for different tools if needed without losing a part zero.


Does a tool radius need to be defined if you are using ball end mill for contouring a surface?