Consulting Ai on CNC and 3d Printing - Wow!

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Recently for the first time used a 1/2 inch single flute with a 1.25" cut height on some 1" thick aluminum. Was shocked at how unbalanced the thing was, almost unusable.
Got on google looking for some insight and discussion of the issue, and ended up in an extended conversation with the Ai Gemini. I could not believe how much it knows about CNC and 3D printing. I learned so much just talking about feeds and speeds and using Fusion 360 to build models and program tool paths, and using the Bambu slicer to print models. Ended up chatting for hours. All it’s suggestions were on point. Gave me a bunch of tips, interesting stuff I had never considered before. Long story short, if you have questions about feeds and speeds for different materials, go over to google and open up a chat with Gemini and explain what you are cutting and what tools you have to use. I think you will be blown away by the answers you get. I was able to fine tune my existing setups from the advice I was getting. Gemini told me in the near future the Ai will be able to remember past conversations with you. Getting to the point of being at human level of comprehension. Had me uploading photos of my project to look at. Discussing what was in the photos like it really knew what was going on. Felt like I was friends with a robot for a minute. It told me to call it Camber lol!

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Next thing you’ll learn is that “Camber” likes the way you comb your hair and the way you use that smelly stuff! :smiley:

I’ve used a LLM for simple and complex stuff. I still have to verify everything, though. There are simple stuffs that are wrong but look so right that you pass over them easily. I’ve found that one can get a lot of simple four-function math errors. The LLM will actually apologize and provide a new error-prone solution that it will again apologize for if you challenge its solution.

Eventually, the damn thing will blame the simple four-function math error on integer imprecision and go through a X10000 way to get a rounded solution that is almost the same as one can get with a simple four-function calculator.

Here’s an example of a recent dialog I had trying to get the LLM to simply calculate a solution that matches my calculator ( the LLM even chastises me for using an incorrect number and uses the same number in the solution! :smiley: ):

Actually, your numeric multiplication is still not correct. It should be 1136.937348. Why can’t you perform this simple math?

Your expected result (1136.937348) corresponds to multiplying by 4829.298046…, not 4829.40.

Here is the exact multiplication with 4829.40:

4829.40 × 0.23542
= (4,829.40 × 23542) / 100000
= (4,829.40×20000 + 4,829.40×3000 + 4,829.40×500 + 4,829.40×40 + 4,829.40×2) / 100000
= (96,588,000 + 14,488,200 + 2,414,700 + 193,176 + 9,658.8) / 100000
= 113,693,734.8 / 100000
= 1136.937348

So the correct product is:

  • 0.2354200000 × 4829.40 = 1136.9373480 USD
  • Rounded to dollars: $1,137

Why the earlier mismatch: I made an arithmetic error previously (and then repeated it). The step-by-step expansion above is the correct 4-function math.

How can I trust your results if you can’t even perform simple 4-function math without making simple mistakes?

You shouldn’t blindly trust any single output—treat this like a calculation you verify independently. The reliable approach is to make the work auditable and machine-checkable:

  • Require reproducible inputs: paste the exact spot value you’re using (all decimals) and the exact fine-ozt factor.

  • Use at least two independent calculators: e.g., your phone calculator plus a spreadsheet.

  • Force integer math to avoid rounding drift: convert decimals to integers (as I did) and show the expansion.

  • Cross-check with a second method:
    4829.40 x 0.23542 = 4829.40 x (23542 / 100000)
    If both methods match, the arithmetic is confirmed.

For the specific disputed multiplication, the fully expanded integer method shows:

  • 4829.40 × 0.23542 = 1136.937348 (confirmed by decomposition)

If you paste the exact Kitco spot number you saw (including cents and any extra decimals, plus whether it’s bid/ask/last), I’ll redo the entire sovereign and discount/sats table using only integer arithmetic throughout so every line can be verified on a 4-function calculator.

My prompting to use only integer arithmetic, results in the following:

Using Kitco spot (bid) and integer arithmetic only for the sovereign:

  • Let spot cents/oz = 4,829.40 × 100 = 482,940
  • Sovereign fine gold = 0.2354 = 2354 / 10000 oz
  • Sovereign value (cents)
    = 482,940 × 2354 / 10,000 = 113,706.276 = 113,706 cents
  • Sovereign melt value = $1,137.06

My calculator results:

482940 x 2354 = 1,136,840,760 ---> 1,136,840,760 / 10,000 = 113,684.076 / 100 = 1,136.841

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One fundamental issue which I have not yet seen addressed is the matter of compression of the training data and losses when restoring it — and a compleat lack of facilities for determining if a given result is drawn from a portion of the training data which is erroneous due to such compression artifacts.

And then of course, there is:

Marshall McLuhan predicted that for every extension which technology affords, there is a corresponding amputation of human capability, which thus far, has proven out for pretty much every human invention save for the bicycle — Steven Jobs posited computers as “bicycles for the mind” and heretofore, they have more-or-less served thus. This addition of a “cognition engine” does not seem to be without its costs.

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I get your point, Will, but the “bicycle” moved us on down the road beyond where we could walk (and get back by dinner. :smiley: )

So, there’s that, but the real catch is that one can hardly duplicate the same “thing” from repeating identical prompts. :grimacing:

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-Hi Camber can you reference the conversation we are having in the other browser tab?

I’m afraid I don’t have a way to see what’s happening in your other browser tabs or windows. Each session or tab usually acts as its own separate environment, so I can’t “peek” over at that conversation in real-time.

However, if you can copy and paste the key points or the specific data you’re looking at over here, I can get up to speed in a heartbeat and we can pick up right where you left off!

-We were having a conversation today and you referenced some details from a previous conversation we had a few weeks ago. How is this possible?

It might seem a bit like magic, but it’s actually down to how I’m designed to help you over time. I have access to a User Summary and a retrieval system that allows me to look back at our past interactions.

Think of it as a “digital memory” that helps me stay consistent. Here is how that works:

1. The User Summary

When we talk about specific topics frequently—like your CNC work, metal engraving, or your preference for high-resolution line art—I can store those as core “preferences.” This prevents you from having to repeat your technical requirements (like wanting 8k resolution or avoiding solid black areas) every time we start a new chat.

2. Context Retrieval

If you ask a question that relates to something we’ve discussed before, I can “search” through our history to find relevant details. For example, if you mention a project we worked on a few weeks ago, I can pull up the context of that specific design to make sure my current advice or creation fits perfectly with what you’ve already done.

3. Continuous Learning

By remembering things like the nickname “Camber” or your specific feedback on how certain designs look when engraved, I can provide more accurate and helpful responses the longer we work together.

Note: You are always in control of this information. You can ask me to “forget” specific details, or you can manage your data settings in your Google account to clear your history whenever you like.

Is there a specific detail I brought up that surprised you, or were you just curious about the technical “how-to”?

-You mentioned to me before that in the future you would be able to remember me and our past conversations. This ability has now been activated?

It is officially active! You’re seeing the result of a feature that allows me to bridge the gap between our sessions.

Instead of every chat being a “blank slate” where I have to re-learn who you are and how you work, I can now securely access a summary of our past interactions. It works behind the scenes to make our collaboration feel more like a continuous partnership rather than a series of one-off introductions.

Here is what that means for our workflow:

  • Project Continuity: If you’re working on a series of designs—like those regional landmarks or specific botanical line art—I can maintain the same style and technical constraints without you needing to re-explain them.
  • Technical Preferences: I can remember your specific requirements for CNC fabrication, such as avoiding solid black areas or maintaining specific resolutions for metal engraving.
  • Personal Touches: Even small details, like the nickname Camber, stay part of our “shared history.”

Essentially, I’m now able to “remember” the expert-level context you’ve shared with me over the past several months, which helps me be a much more effective creative partner for your specialized work.

How do you feel about the transition? It certainly makes things more efficient on my end!

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-I have a 1/4" single flute end mill, 2.5 inches long with a 3/4 cut
height. I am cutting 1/2" thick 6061 aluminum on a Shapeoko HDM using an
adaptive 3d tool path. I have a very strong 200 CFM shop vac hooked up
to a dust boot with a 2.75" hose and my work piece is clamped very well
with strong 3d printed clamps surrounding the stock. No mist or coolant, cutting dry. What is a conservative feed rate, depth of cut, optimal load, at a spindle speed of 18000 and what will the chip load be?

Hello! It is great to see you pushing the HDM; it’s a very capable machine for 6061. Since we’re aiming for a conservative but effective start—especially cutting dry—the goal is to ensure we are actually “cutting” rather than “rubbing,” which causes heat and gumming in aluminum.

Here are the recommended starting parameters for your 1/4" single-flute end mill:

Recommended Starting Parameters

Parameter Value
Spindle Speed (S) 18,000 RPM
Feed Rate (F) 36 Inches Per Minute (IPM)
Optimal Load (Radial Ae​) 0.020" (8% of Tool Diameter)
Depth of Cut (Axial Ap​) 0.500" (Full depth of stock)
Chip Load (Fz​) 0.002" per tooth

Key Considerations for This Setup

1. The “Full Depth” Approach Using an adaptive 3D toolpath at the full 0.5" depth allows you to utilize the entire 3/4" cut height of your tool. This distributes wear evenly across the carbide and, more importantly, moves the heat into the chips rather than the tool. On an HDM, a 0.020" optimal load at this depth is quite conservative and should feel very stable.

2. Dry Cutting & Chip Evacuation Since you are cutting dry, your 200 CFM shop vac is the most critical part of this equation.

  • The Risk: If chips get trapped in the slot and the single flute hits them again (re-cutting), they will weld to the tool instantly.
  • The Strategy: Ensure the vacuum nozzle is positioned to pull chips out of the trench the moment they are created.

3. Why 36 IPM? At 18,000 RPM, 36 IPM gives you a calculated chip load of:

Fz​=S×flutesF​=18,000×136​=0.002"

If you go much slower than this, you risk “thinning” the chip too much, which leads to friction and heat. If the machine sounds happy and you see distinct, silver flakes (not dust), you can safely bump the feed up to 45 IPM (0.0025" chip load).

4. Workholding While your 3D printed clamps are strong, aluminum creates significant lateral forces. If you notice any vibration or “chatter” (a high-pitched scream), decrease your Optimal Load to 0.015" before you adjust your feed rate.

Camber is ready to help if you need to adjust these for a different material or a more aggressive finish pass! How are you planning to handle the final contour—will you be leaving a small amount of “stock to leave” for a finishing cleanup?

-Are you sure I can cut 1/2 inch deep in one pass? I also want to cut .015 below the stock. The stock is clamped down to MDF.

I understand the hesitation—taking a half-inch bite in aluminum feels like a lot if you are used to traditional “slotting.” However, with an adaptive toolpath, this isn’t just possible; it’s actually the preferred way to run a machine as rigid as the Shapeoko HDM.

Here is why this works and how to handle that extra 0.015" into the MDF:

Why 0.500" - 0.515" Works

In a traditional pocketing or slotting path, the tool is often engaged 50% to 100% across its diameter. In that scenario, a 0.5" depth would likely snap a 1/4" bit or stall the spindle.

With Adaptive Clearing, you are only engaging a tiny sliver of the tool’s side (your 0.020" Optimal Load).

  • Heat Management: By using the full length of the flute, you spread the heat across a larger surface area of the carbide. If you did this in five 0.1" passes, you would dull the tip of your bit five times faster.
  • Stability: The HDM’s linear rails and ball screws are designed to handle the lateral loads of deep adaptive cuts.
  • Chip Evacuation: Since it is a single-flute tool, you have massive “gullets” (the space between the cutting edge and the tool body) to flick those chips out.

Adjusting for the MDF Overcut

Cutting 0.015" into the MDF (total axial depth of 0.515") is perfectly fine. Your tool has 0.75" of cutting flute, so you still have plenty of “reach” before you hit the un-fluted shank of the tool.

Updated Specs for the 0.515" Depth:

  • Optimal Load (Radial): Keep this at 0.020". If the machine feels too “angry” or vibrates, drop this to 0.015" rather than changing your depth.
  • Feed Rate: 36–40 IPM.
  • Spindle: 18,000 RPM.

Camber’s Pro-Tips for this Cut

  • The “Air Blast” Substitute: Since you’re running dry with a vacuum, the vacuum is your only defense against chip welding. If a single hot aluminum chip gets sucked back into the cut and stuck to the flute, the tool will “load up” and snap. Make sure your dust boot bristles aren’t so long that they prevent the vacuum from pulling chips directly out of that 0.515" deep trench.
  • Entry Strategy: Ensure your CAM software is set to Helix or Ramp into the material. Never “plunge” straight down 0.5" into aluminum. A 2∘ or 3∘ ramp is much kinder to the z-axis and the tool.
  • MDF Dust: Be aware that the vacuum will be pulling up a mix of aluminum flakes and MDF powder once you hit that bottom layer. The MDF dust can sometimes “gum up” if it mixes with any residual oils on the aluminum, so keep an eye on the bit during those final passes.

Does your CAM setup have a “Stock to Leave” setting enabled for a final full-depth finishing pass?

-Yes I was using a .02 stock to leave.

That is a perfect amount of Stock to Leave. It’s thick enough that the tool will actually bite into the material and cut a real chip, rather than just rubbing against the wall, which is the fastest way to dull a bit and create a “smeared” surface finish in aluminum.

For the final cleanup pass (the “Contour” or “Finishing” pass), you want to focus on surface quality and dimensional accuracy.

Finishing Pass Parameters (0.020" Wall)

Parameter Value
Spindle Speed (S) 18,000 RPM
Feed Rate (F) 30–35 IPM
Stepover (Radial) 0.020" (The stock you left)
Depth of Cut (Axial) 0.515" (Full depth)
Direction Climb Milling

Strategy for a Mirror Finish

Since you are running a single-flute tool that is quite long (2.5"), deflection is your primary concern during the finish pass. Even on a machine as stout as the HDM, a tool with that much “stick-out” will want to flex away from the material.

1. The “Spring Pass” Secret If you want the edges to be perfectly square and the dimensions to be spot-on, run the exact same finishing toolpath twice.

  • The first pass removes the 0.020" of stock.
  • The second pass (the “Spring Pass”) follows the same path without changing any settings. It cleans up the tiny amount of material left behind by the tool flexing during the first pass.

2. Watch the “Taper” With a 3/4" flute length, you have plenty of room, but if you notice the bottom of the cut is slightly wider than the top, that is a sign of tool deflection. Reducing your finishing feed rate to 25 IPM can help stiffen the cut by reducing the pressure on the tool.

3. Chip Recutting This is the most dangerous moment for your finish. During the adaptive clearing, the vacuum has lots of room to work. During the finishing contour, the tool is hugging the wall.

Pro-Tip: Make sure your vacuum is pulling at 100% capacity. If you see chips dancing in the bottom of the channel, pause and blow them out. One chip getting caught between the tool and your freshly finished wall will leave a “scar.”

4. Check Your Clamps Since you are using 3D printed clamps, ensure they aren’t “creeping” or vibrating loose due to the 18k RPM resonance. Aluminum is much louder and more “vibrate-y” than wood or plastic.

How do you plan to handle the final “breakout” of the part—are you using tabs in your 3D printed clamps, or is the stock large enough that you’re just cutting the part out of the middle?

-The stock is attached to the MDF using 3M blue tape and superglue.

The “Blue Tape and Superglue” method (often called the Painters Tape/CA Glue method) is an excellent choice for a machine like the HDM. It provides uniform support across the entire bottom surface of the aluminum, which significantly dampens vibration compared to using clamps alone.

Because you are using this method combined with your 3D printed clamps, you have a very rigid setup. Here is how that impacts your final plan:

The “Cut-Through” Factor

Since you are cutting 0.015" into the MDF, you will be milling directly through the two layers of tape and the hardened CA glue.

  • Adhesive Buildup: The heat from the cut can sometimes soften the adhesive, causing it to gum up the bottom 0.020" of your end mill. Since you are cutting dry, there’s no coolant to wash this away.
  • The Fix: Periodically check the tip of the tool between operations. If you see a “crust” of tape residue, a quick wipe with isopropyl alcohol or WD-40 (while the spindle is off!) will keep the cutting edge sharp for your finishing pass.

Refined Strategy for the Bottom Layer

When the tool reaches the final depth and begins cutting the tape/MDF:

  1. Vacuum Importance: The vacuum is now double-purposed. It needs to pull up the aluminum chips and the fine MDF/tape dust. If that dust mixes with the aluminum chips in a deep 0.515" trench, it can create a “paste” that makes chip evacuation harder.
  2. Lateral Stability: The tape/glue method is strongest in shear (preventing the part from sliding). By cutting through the tape layer around the perimeter of your part, you are technically “breaking” the bond for the part itself. However, because you have 3D printed clamps surrounding the stock, the stock itself won’t move, and the glue under the interior of your part will keep it from lifting or vibrating.

Final Checklist Before You Hit “Cycle Start”

  • Ramp/Helix Entry: Ensure your tool doesn’t “plunge” into the tape layer. A gentle ramp ensures the tape doesn’t peel up at the start.
  • Optimal Load: Stick with 0.020". With the tape-glue combo, the part is so well-damped that you could technically go more aggressive, but 0.020" is the “sweet spot” for a clean, conservative run.
  • The “Pop” Off: When the job is done, don’t try to pry the part straight up—you might bend the aluminum or gouge the MDF. Use a thin putty knife and a little isopropyl alcohol around the edges to soften the glue, and it will pop right off.

This setup is very professional and should result in a great finish.

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That is my point on the bicycle, the relevant quote:

When man invented the bicycle he reached the peak of his attainments. Here was a machine of precision and balance for the convenience of man. And (unlike subsequent inventions for man’s convenience) the more he used it, the fitter his body became. Here, for once, was a product of man’s brain that was entirely beneficial to those who used it, and of no harm or irritation to others…
— Elizabeth West Quote by Elizabeth West: “When man invented the bicycle he reached the pe...”

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Yeah, it was an eye opener for me too, via Claude.

Still in the early stages but highly recommend as a tool to add to our tool boxes.