Machining fixtures making short-run production a piece of cake

Hey Bill,

do you do without constant dust extraction? Is the chip load and the amount of dust always low enough in your work?

Thank you for that information.

I imagine that for many CNCers/machinists there will be quite a lot of variability in what is required for their particular use case/job with respect to things like homing, work offsets, use of fixtures/work holding, required precision level, accuracy, etc …

Right now I am slowly fine tuning my machine parameters for my new ATC set up.
I am trying to work slowly and methodically as I go, and I will share some of my data/results for things like spindle run-out, probe concentricity, homing precision/repeatability, axis calibration, etc in a future update - for those who like data :smiley:

For a set-up like mine, homing repeatability will be important as I will have an auto tool setter and tool rack positions that need to be found and navigated with fair precision. Having the soft limits keep the spindle away from the tool rack at the back will be another use for setting the machine coordinates through homing. I anticipate defining the G54-G59 work offsets to be a real time saver, especially for fixtures for wood projects where hitting the ‘go to work origin’ will get me to the same zero on piece after piece.

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Yes, couldn’t have said it better myself Tom. Every user will have variability in their requirements of homing & work offsets. Buy you bring up an interesting point about ATC. You couldn’t get away with “half-ass” homing like I occasionally do, if you hope to use the ATC functionality. Can’t wait to see more in-depth posts about the ATC setup.

@Aiph5u Yes, the types of materials I carve tend to create more “chips” than actual “dust”. That’s one of the reasons I generally don’t do wood. My shop is so small that I don’t have the room for the auxiliary woodworking equipment (including dust collector). That, and the fact that I like to always see exactly what’s going on with my carves @ the tip of the cutter.

My shop is only 8’ x 12’ [243cm x 365cm], which is suitable for the type of work I like to do.

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Hey Bill,

thank you for providing the metric values, much appreciated :wink: :slightly_smiling_face:

I had seen some images of exterior and interior you showed before, I like it because you accomodate with limited space but you seem to have everything in it.

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Just for you my friend!
You know, as someone who has grown up in the “Imperial” system of measure, I really started getting a deeper appreciation for metric when I first got my X-Carve and started to modify it. Everything is metric based, so rather than fight it and convert everything to inch, I just worked with metric values and learned to embrace it. Makes so much more sense than working in inches. Unfortunately at work, everything is based on imperial measurements (raw stock size, screw sizes, etc.). I did work with metric as the primary unit of measure when I worked at Toyota 2006 - 2012.

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I will have updates soon for sure for anyone interested.

As an aside, in my efforts to dial in the accuracy of my axes, I am putting my new probe to work.
I have one of my 25 50 75 blocks (l prefer metric) in my fixture plate vice, and am probing the long side while keeping track of values in my work offset table. I do three trials to see how far from the 75 mm the values are and take the average. Then I use this to calculate the new adjusted Distance Per Revolution then update the axis. I was not far out originally, but now I am within about .01 mm. Granted, it is just over a 75 mm distance, but my hope is it will be just as accurate as my ‘measure between the two pin hole’ method :grinning: I have a 60 cm precision ruler arriving tomorrow, and I will use it as well to see check the accuracy over a greater distance (which unfortunately relies on my eyes finding the holes and marked ruler increments). I thought as well I could use my digital calipers as well with this technique, albeit over a shorter (~15 cm) distance.

Let’s hope it is not all a mute point once I quantify the backlash on the axes :grinning:

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Before I got certified to be an Xometry partner, I had ordered a 10" ‘B Grade’ standard block that I was going to use to calibrate my machine over 10". It never came (out of stock, apparently) so I ended up using (2) 1 2 3 blocks end-to-end and calibrating over 6". As I recall, I didn’t have to tweak the settings at all. Factory default values were dead-on (and mathematically, why shouldn’t they be?). For whatever reason, outside profile cuts are spot-on when I do a finish pass, but holes are typically slightly less than 0.1mm undersize, which I usually deal with by fudging the actual cutter size.

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Lol!

I enjoy thinking of the time when we will have retrofit glass scale linear encoders to our machines and be finally satisfied :slight_smile:

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I remember a while back when your parts were accepted by Xometry, and thinking that bodes well for the 1F and my plans for it. Albeit a slighter larger size, my hope is to get the same accuracy and precision from it as you have, at least to the best of my ability and measuring instruments.

I really am looking forward to making parts. Not so much worried about the wood projects I have in mind, as I feel they will be inherently more forgiving the the aluminum work I wish to accomplish.

I imagine you needed to prove some fairly tight and repeatable tolerances for Xometry approval.

Well, in the case of the test part it was demonstrating you could hold +/- 0.005" [0.13mm]. The exception to this was the very tight tolerance on the (2) 0.062" [1.575mm], which I purchased a reamer to do these holes with. I bought $44 worth of misc. tooling to do this job, which in addition to being accepted as a partner, they paid $100 for. They sent enough material to do 2 parts (which I did).

I have a very restrictive job filter set up, so whatever makes it past the filter I can at least look at & consider. I think this current job I’m doing is #13, and I’ve been a partner for just less than 1 year. I only take on what I’m absolutely sure I can do without problem.

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That is a smart way of doing it. I can only imagine the variety of projects that make it your way, and through that platform in general. Must be interesting work.

Well, a lot of it is pretty interesting (compared to my day job, lol). But you can really tell that a lot of the parts are designed by very inexperienced designers. I’ve seen parts that aren’t even producible on a 5-axis machine. Many would be candidates for 3D printing, but they’re not tagged as such. There doesn’t seem to be any DFM review on these parts, which I squarely place the blame on Xometry for these parts even making it to the job board. On jobs I’ve done in the past, I’ve started contacting the customer directly (once I have their name & shipping address) with one of my coasters and a note inviting them to contact me directly if they were happy with the parts I made for them thru Xometry.

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Over the past 2 weeks I’ve added proximity sensors for homing on the X and Y axis (still working on Z but need some more downtime) and I have been pleasantly surprised on the repeatability and accuracy they have provided to the homing cycle and using that as the basis for work offsets. I have both a metric digital dial indicator and a imperial mechanical dial indicator and through 50+ homing sequence tests with controller reboots between some the error is immeasurable on my indicators .005mm and .0008" resolution respectively although you can estimate the dial indicator to .0002". I was hoping to hold .003" on homing but it has proven to be far more repeatable than expected.

For backlash testing using the same equipment I have observed 0.000mm or 0.005mm, on a machine with about 1200 hours on it (Journeyman upgrade X axis is closer to 500 hours)

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That is encouraging. I look forward to measuring similar results over the next few days of set-up. What testing method did you use to determine homing repeatability of the X and Y axes?

I used two different methods using the stock Onefinity controller

First I performed testing to see the general repeatability of the sensor treating it as a probe wired to the controller where I created a g code program to run the axis toward the sensor at a feed rate of 50mm/min, when the sensor was activated it would stop and I had it record the offset from machine 0, then it would back off 10mm and run again with the following results (this is the Onefinity measuring itself in mm):

I then reconfigured the switch as a limit and changed the homing configuration to use the proximity sensor instead of stall homing. Homed it one time, move it 100mm away from the sensor and used that to zero the dial indicator. Ran the homing cycle again, back off 100mm and measure delta, repeated about 20 times with no variation in the measurements. Moved on to rebooting the controller then homing the machine followed by backing the axis off 100mm and again no delta in the measurements. Started thinking the digital indicator was playing tricks so I went to the mechanical dial indicator, same results. I moved the dial indicator base in a couple mm and re-zeroed the indicator just to make sure I wasn’t hitting a odd spot in the equipment but the results remained the same throughout.

Thank you for sharing the process, I appreciate it. It seems similar to what I had done when I set up my first build.

Are you indicating off a tool/shaft in the collet, or a part of the frame/mount?
After homing, are you moving the 100mm in one direction/along one axis towards the indicator?

I have my Masso controller set a Z>X>Y homing sequence. It means I can’t test in the Y axis direction as the indicator would be hit during homing. If I remember, I may have indicated therefore in the X direction. Also, I think I indicated off a flat surface of the mount or Z assembly, making sure the surface hit the probe at a 90 degree angle each time.

Homing repeatability for my new ATC build is important as the machine coordinates will need to precisely locate my tool setter, and more importantly the tool rack positions. I think for my repeatability testing this time I will locate the indicator an XY position from home. For example, using MDI command X100Y150 (or similar) after homing. I also was thinking of creating test positions by creating a few G54-G59 work offsets. So after homing I would use MDI to select a work offset, then go to work origin, and it would move to the test indicator set up there. I was thinking this would be like it having to find a tool holder position on the rack.

My next next update will be all about numbers, and the results of testing such as described above.

Wow Derek, that is encouraging. That’s some pretty impressive repeatability. I’ve got a bunch of prox sensors I bought when I had my X-Carve but never used them. Might have to reconsider my homing process and maybe work on mounting these sensors I’ve got.

I was using the spindle body as it was the most convenient spot I could get the dial indicator set up and oriented where I could see it.

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@TMToronto Tom, does the ATC use actual machine coords (dim. from home position) to locate the tools in a library, or do you have to dedicate one of your work coords to the tool change process? (hope that question makes sense, it does in my head. :rofl: )

I understand your question.

I 3D printed my own holders, and instead of forks will use the ,pick and place, arrangement for the holders. Below is a section of the Masso manual…

Defining the Tool Position

  • The Center of each slot is defined by the Slot #: X, Y position parameter box.
  • :grinning:These coordinates are used to define the tool position and are Machine coordinates.
  • The values are defined in the native unit of measurement, either metric or imperial that you have set under general settings in the F1 Screen.
  • Because each tool holder’s position is defined by both an X & Y coordinate you can place the tools anywhere on the table.
  • When using a Pick and place tool holder you can define multiple rows of tools.

INFORMATION: Tool slot coordinates can be located outside of the machine’s soft limits.

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