Page is under construction by colinl. Work in progress.
This page documents procedures on Jaxen that should be followed when doing any projects. Purposes of this guide:
This page is only for Jaxen, although some general info about milling may apply to other CNC machines. Started by colinl.
todo: add link to here from member-written guides.
The Training Program for Jaxen will teach you all the following skills:
Housekeeping:
Milling:
CNC:
CAD:
The roadmap:
After you have been trained and your name is added to the list of trained people, and you've completed the training demo project, you can begin your own projects. For your first project, you must discuss your project plan with a CNC committee member who is currently offering training. This is to help you apply the skills you learned from the training to new scenarios. Also, experienced members can help you get what you want: either fast production, or high quality. Be sure to tell them what you want. On your second and later projects, you are encouraged to ask for advice, but you can begin using the machine without the need for permission, while still minding other's access to the machine.
Installing collets into the spindle:
It is very easy to drop bits when doing this. They chip when they fall! You need to touch 3 points of contact when installing collets:
Put lower fingers on the bit, upper fingers on the collet. When installing a collet, put it in by hand first, then hand tighen the bolt on the top of the “draw bar”, then 1/4 turn with wrench, then REMOVE allen key immediately!!
Always ensure the Allen Key is out of the top screw after tightening spindle!!!
The “draw bar” mates with threads on the top of the collet.
Squaring stock:
Identify the flattest faces to use as clamping faces, then face the roughest first. Next, put this newly faced face against the jaws, and face the next face, 90* from the first.
However, when clamping, use a round stock against the unfinished face to prevent it from altering squareness.
Continue using these principles. For the last 2 sides, can use an endmill bit to make faces perpendicular to the spindle axis.
Top-hat method:
Good for when you don't need fully-faced sizes, but complete top and bottoms. (There is no way to accurately face the full sides using this method)
Slots:
For plunging, you need an endmill with center-cutting ability (no center hole). When plunging, the bit will vibrate, causing hole size to be slightly larger than the bit's size. Width of slot is dependent on rigidity of machine. Blondiehacks example: 1/4“ cutter, 1/8” steel plate. For ideal finish, make a slot in 3 passes: 1 smaller rough pass, then go back around the edges to get final dimension (3thou is a good amount to take off)
Blind Slots:
Additional issue is chip control, gets worse for deeper slots.
Can use a chamfering tool for final step as an alternative to deburring.
Facing:
If you climb-cut a face around the edges, it won't produce a burr, because the burr is sucked inwards and naturally cut off.
Speed and feed resources:
Used by myelophone: https://www.autodrill.com/resources/recommended-tool-speed-chart Notes: above assumes: HSS tools, appropriate coolant (although says you can reduce RPM by 25% to not use coolant in “most metals”, stainless requires more reduction).
https://www.carbidedepot.com/formulas-turning.htm
Why is workholding needed?
If you're going to be milling most sides of your part to be non-flat, you can't clamp your part in a vice. You'll need to hold it by it's middle somehow.
Examples: gears, oddly-shaped flat parts, decorative items, etc.
By using a standard hole, this has 2 functions:
You MAY need a custom mount if:
You will definitely need a custom mount for your part if:
The standard mounting method currently is M6 threaded holes spaced 10mm apart, passing through non-threaded holes in your workpiece. Reccommended to use hex bolt heads so that the head can be as large as possible wihtout needed to use a wrench because it would hit adjacent bolt heads.
Preparing workholding for your project:
You will need to drill an exact-sized hole in your stock to fit snugly on the M6 bolt. Reccommended: 15/64 in == 5.95mm. The M6 bolt should be snug, but just barely slide through the hole in your workpiece. Then, you'll need to use the existing threaded mounting holes in the bed, or make new ones:
First drill pilot holes with a 1/8 bit in the mill for accurate pilot hole locations.
Then a 13/64in (5.16mm) bit on other machine/drill to prepare for tapping, (because it's harder to find a collet for)
Or you can use the R8 drill chuck to directly drill this hole on the mill.
then tapped using an M6 tap.
Types: Arbour/Shell mill? Chamfer/bevel Ball mill End mill
Hobbyist generally shouldn't use carbide tips, has stricter limitations for feeds/speeds. Instead, use high-speed steel.
4 flute is better for cutting steel, 2 flute is good for alum,brass Corn cob bit is for roughing, can feed faster.
Recommended setups:
R8 collet > 1/8 bit - examples: V bits 20deg, gold cordcob endmills,
R8 collet > 1/4 bit - examples: yellow ball nose
R8 collet > 1/2 bit - examples: endmills
R8 collet > 5/8 bit - examples: endmills
ER16 collet > 6mm bit - examples: 6mm endmills
ER20 collet??? > 3/16 bit - example: V bit 90deg
Aluminum: WD40 Stainless-Steel: Anchorlube Metalworking Compound
316 Medical Grade stainless steel is used for food/body safe items.
Flat stock has internal stresses that cause a phenomenon where the part may warp in a direction parallel to the surface. Cast stock avoids this problem.
Grease goes in harder-to-reach places, oil for ways.
High-pressure grease, for lubricating gears or parts that have high forces between them, but typically sealed. Blondiehacks reccommends: MAG1 High Temp Disc Brake Wheel Bearing Grease Lithium Complex https://www.youtube.com/watch?v=x8tx-cBulno
Oil the machine before every long-use of the machine. (frequency to be determined for Jaxon)
Never use acidic cleaners (Clorine, bleach) because it causes rust!!
Great G-Code reference:
Marlin Firmware G-Code Reference
General tips:
Job prep: For example, choosing inside corner radii based on bits used.
-Work from the inside out, because the outer material is what typically touches the vice, and also the perimeter is usually more volumeous than the inner parts, so it makes the part more rigid for longer during the job.
-Do blind pockets in steps, because the deeper any single pass, the more the bit will vibrate, and this makes the walls rough. Additionally, the final pass should be very thin for the best finish.
-When running your code in UCCNC, you click the CYCLE START button. BE CAREFUL that this actually starts from the current line! If you scrolled your file, or partially ran your code before, it will resume, not restart!!
M6 = Tool change. Usually exported b FreeCAD, but ignored for our machine. M3 sNNNN = set spindle RPM
Note that the GCode can be specified in: Absolute: G90 Relative: G91
G53 #0 = Machine Coordinates, where 0,0,0= the homing position. G54 #1 = User defined #1. G55 #2 = User defined #2 … G59 #6 = User defined #6 WARNING: when axis is homed, any error corrected will cause all workspaces to shift by that amount! DO NOT HOME the machine between operations! This is because all user-defined workspaces are relative to/nested inside Workspace #0. However, they are not all nested within each other consecuitively. Example: Workspace #2 is not affected by workspace #1, only Workspace #0.
There is one more offset: the “tool offset” which is nested in every workspace. It only affects Z. Note that this is not the same as “tool radius compensation”.
In UCCNC: In the “Main” window 3D view, the blue pointer represents the origin of the SELECTED workspace. The yellow is the actual toolbit location relative to the selected workspace.
Setting workspace coordinates: Do this before starting to execute CAM GCode. In the CAM software, usually it will say what workspace # you are exporting for. In UCCNC, activate the workspace you want: G54 Then, manually move the bit to the origin point you want to use. (using the “manual drive” buttons in UCCNC) Then you need to save this position into UCNC as the origin for Workspace #1. Do this by typing the command: G92 x0 y0 z0 OR you can click “ZERO ALL” blue button. The current position is now set to be the origin for Workspace #1.
A G0 is used for a “rapid move” (at the machine's native feed rate) Theory: a G0 move will not necessarily be a straight line: each axis moves independently and max-out speed independently. The controller will decide the best way to get to destination. For example, it will always move Z up first before X/Y???? And then a G1 is used for cutting (interpolated) Also, G0 uses the machine's built-in feed rates, whereas G1 uses the last feed rate specified.
For semi-manual G-Code, cheatsheet: MDI = Manual Data Input box First check: #Relative positioning: G91 #Interpolated move: G1 F1 Z1
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