Initializing the Mill

To prepare the mill for motion, the mill must be initialized.

Vital Reference

After powering on, the PCNC mill must be referenced in the X-, Y-, and Z-axes. Execute the referencing procedure as follows:

1. Power on the mill following the power off/on procedure, Installation.

2. Click the flashing Reset button on the PathPilot interface.

3. Click REF Z, REF X, and REF Y.

Jogging

Manual Control Group

The Manual Control Group’s buttons and slider allow the operator to perform tasks related to manual control of the mill, including jogging the mill axes, changing the current tool number, feed rate, or spindle speed, and starting or stopping the spindle (see Figure 2.3).

Jogging Controls: Tormach mills can be jogged with either the Jog Shuttle (PN 30616) shown in Figure 2.5 or by using the keyboard’s arrow keys (see Figure 2.4):

• The right arrow jogs X-axis in the positive X direction (table moves left of operator).

• The left arrow jogs X-axis in the negative X direction (table moves right of operator).

• The up arrow jogs Y-axis in the positive Y direction (moves table towards operator).

• The down arrow jogs Y-axis in the negative Y direction (moves table away from operator).

• The Page Up key jogs the Z-axis in the positive Z direction (moves spindle up).

• The Page Down key moves the Z-axis in the negative Z direction (moves spindle down).

Figure 2.3 – Manual Control Group

Figure 2.4 – Jogging with Keyboard Keys

Figure 2.5 – Jog Shuttle

Spindle Controls

Manual Spindle Control Via Operator Panel

The operator panel-based spindle controls are outlined below:

• To control the spindle via the Operator Panel switch the spindle to Manual (see Figure 2.2).

• Use the Spindle Speed Dial to select the desired spindle RPM. The numbers correspond to spindle speeds when the belt is in the high position.

• Use the spindle direction switches to select Forward for clockwise and Reverse for counterclockwise.

• Press Start to activate the spindle. Press Stop to stop the spindle.

Automated Spindle Control Via PathPilot Interface

To control the spindle via the PathPilot interface, switch the spindle to Auto on the Operator Panel (see Figure 2.2).

Changing Spindle Speed Range

Each PCNC mill has two speed ranges as outlined in the table below.

The range change is performed by moving the spindle belt from the top pair of pulleys (high speed range) to the lower pair of pulleys (low speed range).

Tool Holders

This section describes using tooling compatible with the standard R8 spindle. For more information on other spindle options, refer to the product-specific documentation.

The Tormach Tooling System (TTS) is the recommended tool holding method for PCNC mills. The advantages of TTS over other tooling options include:

• Exact tool offset repeatability

• Easily adaptable to tool presetting techniques

• Quickest manual tool change time

• Shortest tool change clearance distance

• Compatibility with Tormach power drawbar and Tormach automatic tool changer (ATC)

Part Setup/Workholding

Work must be secured to the table prior to machining. Each PCNC mill has three 5/8” T-slots that run parallel to the X-axis. The slots are precision ground to:

References: 3 gen. [106-109]

Assessing questions:

1. How the Tormach PCNC 1100 mill is working?

2. What parts contain Tormach PCNC 1100 mill?

3. Why we use jogging?

4. How to use Spindle Control?

5. Why it is necessary to use Tool Holders?

Practical work № 3

Title: Creating own 2D and 3D design project (on Compass or SolidWorks) with given specifications and tolerances.

Task: To create 2D/3D drawings by using CAD systems.

Solution:

Creating 2D drawing

1. Save the file as ab1.dwg in your AutoCAD folder. ORTHO is on and units are set to Fractional. Choose Tools➪Drafting Settings (or right-click OSNAP on the status bar and choose Settings) and set running object snaps for intersection, center, and endpoint. Make sure OSNAP is on. In this exercise, you draw part of the sealing plate shown in Figure 3.1.

Figure 3.1: The dimensioned sealing plate for a valve

2. Start the LINE command. Start at 2,3 and use Direct Distance Entry to create a 7-unit horizontal line to the right. End the LINE command.

3. Draw another line starting at 5-1/2,1-5/8 and draw it 2-3/4 units long in the 90- degree direction. These two lines are center lines and would ordinarily appear

in a different color and linetype than the object you are drawing.

4. Draw a circle with its center at the intersection of the two lines (use the Intersection object snap) and a radius of 11⁄16.

5. Use the Center object snap to draw another circle with the same center as the first circle and a radius of 1.

6. Draw a third circle, using the From object snap (Shift+right-click to open the object snap menu). For the base point, use the Center object snap and pick either of the first two circles you drew. The offset is @-1-15/16,0 (this means 1-15/16 units to the left of the center of the first two circles). Its radius is 3⁄8.

7. Draw a fourth circle. Use the From object snap again. For the base point, use the Center object snap and pick either of the first two circles. The offset is @1-15/16,0. The radius is 3⁄8.

8. Choose Arc from the Draw toolbar. Follow the prompts

Specify start point of arc or [Center]: Choose the From object snap.

Base point: Use the Center object snap to pick the center of the leftmost circle.

<Offset>: @-5/8,0 ↵

Specify second point of arc or [Center/End]: Right-click and choose Center. Use the Center object snap to pick the center of the leftmost circle.

Specify endpoint of arc or [Angle/chord Length]: Right-click and choose Angle.

Specify included angle: 67.23 ↵

4. Start the LINE command. At the Specify first point: prompt, press Enter to continue the line in the same direction as the end of the arc. At the Length of line: prompt, type 1-13/16 ↵. End the LINE command.

5. Choose Arc from the Draw toolbar. Follow the prompts:

Specify start point of arc or [Center]: Use the Endpoint object snap to pick the end of the line you just drew.

Specify second point of arc or [Center/End]: Right-click and choose Center. Use the Center object snap and pick any point on one of the large central circles.

Specify endpoint of arc or [Angle/chord Length]: Use Endpoint object snap to pick the lower end of the vertical construction line.

4. Repeat the ARC command. Follow the prompts:

Specify start point of arc or [Center]: Right-click and choose Center. Use the Center object snap and pick any point on one of the large central circles.

Specify start point of arc: Use the Endpoint object snap to pick the endpoint of the arc you just completed.

Specify endpoint of arc or [Angle/chord Length]: Right-click and choose Angle.

Specify included angle: 22.77 ↵

4. Start the LINE command. At the Specify first point: prompt, press Enter to

continue the line in the same direction as the end of the arc. At the Length of line: prompt, type 1-13/16 ↵. End the LINE command.

4. Start the ARC command. Follow the prompts:

Specify start point of arc or [Center]: Use the Endpoint object snap to pick the endpoint of the line you just drew.

Specify second point of arc or [Center/End]: Right-click and choose End.

Specify endpoint of arc: Choose the From object snap.

_from Base point: Use the Center object snap to pick the center of the rightmost circle.

<Offset>: @5/8,0 ↵

Specify center point of arc or [Angle/Direction/Radius]: r ↵

Specify radius of arc: 5/8 ↵

13. Save your drawing.

Creating 3D drawing

Using 3D Coordinates.

1. Choose Rectangle from the Draw toolbar. At the Specify first corner point or [Chamfer/Elevation/Fillet/Thickness/Width]: prompt, type 0,0,19 ↵. At the Specify other corner point or [Dimensions]: prompt, type 39,15 ↵. This creates a rectangle 39 units long by 15 units wide that is 19 units above the plane created by the X and Y axes. Notice that you omit the Z coordinate for the second corner.

2. Start the COPY command. To copy the rectangle 2 units above the original

rectangle, follow the prompts:

Select objects: Pick the rectangle.

Select objects: ↵

Specify base point or displacement, or [Multiple]: 0,0,2 ↵

Specify second point of displacement or <use first point as displacement>: ↵

You now have two rectangles, but because you are looking from the top, you see only one.

Choose SE Isometric view from the View flyout of the Standard toolbar.

Now you can see the two rectangles, as shown in Figure 3.2.

Figure 3.2 – The two rectangles, shown from Southeast isometric view

3. If OSNAP is not on, click it on the status bar. Set a running object snap for endpoints

4. Start the LINE command. Follow the prompts:

Specify first point: Pick the endpoint at 1 in Figure 21-7.

Specify next point or [Undo]: 0,0,0 ↵

Specify next point or [Undo]: 1,0,0 ↵

Specify next point or [Close/Undo]: 1,0,21 ↵

Specify next point or [Close/Undo]: ↵

5. Start the COPY command. At the Select objects: prompt, select the three lines you just drew. End object selection. At the Specify base point or displacement, or [Multiple]: prompt, type 38,0,0 ↵. At the Specify second point of displacement or <use first point as displacement>: prompt, press Enter. AutoCAD copies the three lines. Because the bench is 39 units long and the legs are 1 unit wide, copying the leg 38 units in the X direction places the copy in the right location.

6. Do a Zoom Extents so you can see the entire drawing.

7. Repeat the COPY command. Use two separate crossing windows to select the first leg, then the second leg. AutoCAD should find three objects each time.

End object selection. At the Specify base point or displacement, or [Multiple]: prompt, type 0,15,0 ↵ to copy the legs 15 units in the Y direction.

Press Enter at the Specify second point of displacement or <use first point as displacement>: prompt. AutoCAD copies the legs to the back of the bench.

8. To draw an open cover for the piano bench, start the LINE command. Start it at the endpoint at 2 in Figure 21-7. At the Specify next point or [Undo]: prompt, type @15<90<45 ↵. You know the length of the line because the cover is the same as the width of the piano bench. At the Specify next point or [Undo]: prompt, turn on ORTHO, move the cursor parallel to the length of the bench, and type 39. At the Specify next point or [Close/Undo]: prompt, use the Endpoint object snap to pick 3. End the LINE command.

Zoom out and pan so you can see the entire bench.

9. To draw some bracing inside the bench, start the LINE command again. At the Specify first point: prompt, choose the endpoint at 4. At the Specify next point or [Undo]: prompt, type @15<90,2 ↵. End the LINE command. Here, cylindrical coordinates are ideal because you don’t know the length of the line but you know the change in the X and Z coordinates (the width and the height of the bench’s body, respectively).

10. Save your drawing. It should look like Figure 3.3.

Figure 3.3 – The completed wireframe piano bench

References: 3 gen. [124-125]

Assessing questions:

1. How the 3D objects are created?

2. What is the OSNAP?

3. Why the 3D objects cannot be cut?

4. How to ZOOM 3D objects?

5. Why it is necessary to know 3D object tools?

Practical work № 4

Title: Programming own project on CAM system (on Esprit or another).

Bridgeport CNC Checklist

1. The XY plane needs to be located at the top of the part in the CAM software

a. XY plane or Z0.0 = top most feature of part

2. Create NC file (Posting processing)

a. Can create one NC file with multiple tool operations (Tools of different size/type)

b. Or make separate NC files (Useful if cycle times are long)

c. Use the “Bridgeport.asc” post processor file if using Esprit CAM

d. Load NC file onto floppy disc

3. Setup Bridgeport mill

a. Fixture part on mill

b. Setup coolant mister if needed

c. Set X0 and Y0 datum origin points

i. Use the edge finder to locate the (X0,Y0) point that matches the origin you

set in the CAM program.

ii. Offset for the edge finder radius

iii. On machine panel set X0 and Y0 datum points

1. “DRO” button > Datum > X & Y = 0.000 > “USE” button

d. Load the first tool

e. Engage the Z axis servo

i. Unlock and raise quill all the way up

ii. Rotate servo engagement knob fully clockwise to engage Z axis servo

f. Make sure knee is set at the appropriate height

i. Adjust knee height to reduce excessive quill extension

ii. Leave approximately 1” of quill stroke above top of part for tool retracts

g. Set Z0 datum origin point

i. Lower tool until it touches the top of the part (Z0 origin set in CAM)

1. Perform either static (spindle off) or dynamic (spindle on) zero

ii. On machine panel set Z0 datum point

1. “DRO” button > Datum > Z = 0.000 > “USE” button

h. Set tool retract height

i. On machine panel:

1. “DRO” button > Datum > Tool retract = 0.5” > “USE” button

i. Manually raise quill above the top of the part (approx. 0.5” clearance)

4. Load program NC file

a. Insert floppy disc on front panel of machine

b. Load program from floppy

i. “PGM” button > Program Functions > Load > Use Floppy > Change format to “Gcode”

> Pick Program > “Enter” button

5. Run Program

a. Place multiple safety shields around the part/fixture setup

b. Double check cursor is at the beginning of program (top most G code line)

c. Ensure tool is approximately 0.5” above the part

d. Take quill handle off

e. Retract knobs on X and Y axes handles

f. Turn spindle on and set spindle speed

g. Turn coolant on

h. Start program by selecting the green “GO” button

i. Keep finger on red “STOP” button in case of emergency

j. Press green “GO” button to confirm actions shown on screen

In case of emergency

a. Stop CNC motion by pressing the red “STOP” button

b. Turn off spindle

7. For NC programs that require tool changes:

a. Start the CNC program as described above with the first tool

b. At the end of the first tool operation, the machine will retract and pause.

i. Machine display will indicate to switch to the next tool number

ii. Press the red “STOP” button once

c. At this point, manually perform the tool change procedure for the next tool

i. You may move the X and Y axis handles if needed. This will not lose the X

and Y datum points.

ii. Turn on spindle and adjust spindle speed for new tool

d. Once the second tool is inserted, the Z axis datum point needs to be reset.

i. Move X and Y axis handles so that the new tool can touch the top surface

ii. Readjust knee height to reduce excessive quill extension (leave 1” of quill

stroke above the top surface of the part)

iii. Set Z0 datum origin point

1. Lower tool until it touches the top of the part (Z0 origin set in CAM)

a. Perform either static (spindle off) or dynamic (spindle on)

zero

2. On machine panel set Z0 datum point

a. “DRO” button > Datum > Z = 0.000 > “USE” button

3. If no original top surface still exists, touch off a surface of known Z

height, then set Z datum to the known negative distance.

a. Check Z datum origin point by manually raising the quill to

absolute Z0.000 and verify the tool is at the correct height

e. Manually raise quill above the top of the part (approximately 0.5” clearance)

f. Press “PGM” button to return to the program screen

g. Turn spindle on

h. Continue the program by pressing the green “GO” button

References: 3 gen. [125]

Assessing questions:

1. What is CAM systems?

2. Application of CAM software.

3. What we need to do in case of emergency?

Practical work № 5

Title: CNC programming. Selection of operation for machining.

Tasks: To learn G-Code programming. Given part in following figure 1.

Figure 1 – Part material: Aluminum 6061

Solution:

A line in a G-code fi le can instruct the machine tool to do one of several things.

Movements

The most basic motion for a controller is to move the machine tool along a linear path from one point to another. Some machine tools can only do this in XY, and have to accept changes in Z separately.

Some have two further axes of rotation to control the orientation of the cutter, and can move them simultaneously with the XYZ motion. Lately 4 and 5 axis machines have become popular. The 2 additional axis allow for the work surface or medium to be rotated around X and Y. For example, a 4-axis machine can move the tool head in XY and Z directions, and also rotate the medium around the X or Y axis, similar to a lathe. This is called the A or B axis in most cases.

All motions can be built from linear motions if they are short and there are enough of them. But most controllers can interpolate horizontal circular arcs in XY. Lately, some controllers have implemented the ability to follow an arbitrary curve (NURBS), but these efforts have been met with skepticism since, unlike circular arcs, their definitions are not natural and are too complicated to set up by hand, and CAM software can already generate any motion using many short linear segments.

With the advent of the vortech router cnc quad drive system which utilizes four (bidirectional) motors and drive, users are able to achieve greater speeds and accuracy.

Drilling

A tool can be used to drill holes by pecking to let the swarf out. Using an internal thread cutting tool and the ability to control the exact rotational position of the tool with the depth of cut, it can be used to cut screw threads.

Drilling cycles

A drilling cycle is used to repeat drilling or tapping operations on a workpiece. The drilling cycle accepts a list of parameters about the operation, such as depth and feed rate. To begin drilling any number of holes to the specifications configured in the cycle, the only input required is a set of coordinates for hole location. The cycle takes care of depth, feed rate, retraction, and other parameters that appear in more complex cycles. After the holes are completed, the machine is given another command to cancel the cycle, and resumes operation.

Parametric programming

A more recent advancement in CNC interpreters is support of logical commands, known as parametric programming. Parametric programs incorporate both G-code and these logical constructs to create a programming language and syntax similar to BASIC. Various manufacturers refer to parametric programming in brand-specifi c ways. For instance, Haas refers to parametric programs as macros.

GE Fanuc refers to it as Custom Macro A & B, while Okuma refers to it as User Task 2. The programmer can make if/then/else statements, loops, subprogram calls, perform various arithmetic, and manipulate variables to create a large degree of freedom within one program. An entire product line of different sizes can be programmed using logic and simple math to create and scale an entire range of parts, or create a stock part that can be scaled to any size a customer demands.

Parametric programming also enables custom machining cycles, such as fixture creation and bolt circles. If a user wishes to create additional fixture locations on a work holding device, the machine can be manually guided to the new location and the fixture subroutine called. The machine will then drill and form the patterns required to mount additional vises or clamps at that location. Parametric programs are also used to shorten long programs with incremental or stepped passes. A loop can be created with variables for step values and other parameters, and in doing so remove a large amount of repetition in the program body.

Because of these features, a parametric program is more efficient than using CAD/CAM software for large part runs. The brevity of the program allows the CNC programmer to rapidly make performance adjustments to looped commands, and tailor the program to the machine it is running on. Tool wear, breakage, and other system parameters can be accessed and changed directly in the program, allowing extensions and modifications to the functionality of a machine beyond what a manufacturer envisioned.

There are three types of variables used in CNC systems: Local variable, Common variable, and System variable. Local variable is used to hold data after machine off preset value. Common variable is used to hold data if machine switch off does not erase form data. The System variable this variable used system parameter this cannot use direct to convert the common variable for example Tool radius, Tool length and tool height to be measured in mm or inches.

There are other codes; the type codes can be thought of like registers in a computer

• X absolute position

• Y absolute position

• Z absolute position

• A position (rotary around X)

• B position (rotary around Y)

• C position (rotary around Z)

• U Relative axis parallel to X

• V Relative axis parallel to Y

• W Relative axis parallel to Z

• M code (otherwise referred to as a “Miscellaneous” function”)

• F feed rate

• S spindle speed

• N line number

• R Arc radius or optional word passed to a subprogram/canned cycle

• P Dwell time or optional word passed to a subprogram/canned cycle

• T Tool selection

• I Arc data X axis

• J Arc data Y axis.

• K Arc data Z axis, or optional word passed to a subprogram/canned cycle

• D Cutter diameter/radius offset

• H Tool length offset

G-Code programming is a very simple programming language. When we were kids, we used to and may still do connect the dot puzzle games. G-code works exactly on the same principle. It takes two simple concepts to understand G-code programming, connect-the-dots and the number line.

Connect-the-dots

We can draw something very simply by connecting the dots.

We do not think about it, but we are creating something tangible in the 2-axis world.

The Number Line

The number line is simply the measurement of units. Let’s look at this number line:

In a straight line numbers either get bigger or smaller from Zero. Machining, along with G-Code programming, uses both sides of Zero.

Signs +/ -

The Plus (+) sign and the Minus (-) sign are very important in machining. In machining we can also call them Positive or Negative respectively. We use these signs in two situations; location and direction.

Location

They signify what side of Zero a number is on, we can say this is a location indicator; Left for Minus and Right for Positive respectively from Zero.

Direction

These signs also are used as a tool to tell us which direction to move; Left for Minus and Right for Positive.

Standard G-Codes - Mill

The G-Codes are what tell the machine to do with positional reference. This is just a simple reference to what standard G-Codes do.

G0 or G00 – Rapid Movement

The fastest the Machine can go to the next defined position. If moving in multiple axis, each axis will move as fast as they can independently of one another until it reaches it’s defined end points.

G1 or G01 – Linear Movement

A straight line move with a speed defi ned by an F. If moving in multiple axes, the machine will move proportionally in each axis until it reaches its defi ned end position.

G2 or G02 – Interpolation Clockwise

A circular movement in 2 axis. Will create an arc to a specifi ed radius defi ned by R or I/J.

G3 or G03 - Interpolation Counter Clockwise

A circular movement in 2 axis. Will create an arc to a specifi ed radius defi ned by R or I/J.

G4 or G04 – Dwell

Machine will dwell once reached position to a user defi ned time, P.

G9 or G09 – Exact Stop/ Exact Position

Machine will not traverse to next line of code until it positions exactly to position.

G10 - Data Setting

G17 - XY plane selection

G18 - ZX plane selection

G19 - YZ plane selection

G20 - Machine in inch

G21 - Machine in MM

G28 - Return to Reference Position

Normally machine home.

G30 - Return to 2^nd reference position

Normally pallet changing/tool change home if different than machine home.

G40 - Cutter Compensation Cancel

G41 - Cutter Compensation Left

Used with user defi ned value, D

G42 - Cutter Compensation Right

Used with user defi ned value, D

G43 - Tool Length Compensation +

Used with user defi ned value, H. Common

G44 - Tool Length Compensation -

Used with user defi ned value, H. Not common

G49 - Tool Length Compensation Cancel

This program is a Milling program, programmed to the side of the tool.

The Part Zero for programming purposes of this part are:

X0 = Left Edge of Part

Y0 = Bottom Edge of Part

Z0= Top of Part

G-Code Program

%

O0001(PROGRAM#)

(PROGRAM NAME - PART1)

(SAMPLE PART)

N1( 1” FLAT ENDMILL TOOL )

T1M6

M1

N100G0G90G54X-1.Y0.S3056M3

G43H1Z.1M8T2

(PROFILE)

G1Z-1.F24.4

G41D51X-.5

Y1.75

G2X.25Y2.5I.75

G1X3.5

G2X4.5Y1.5J-1.

G1Y.75

G2X3.25Y-.5I-1.25

G1X0.

G2X-.5Y0.J.5

G1G40X-1.

G0Z.1

(FINISH WALL STEP3)

X1.25Y4.5

G1Z-.5

G41D51Y4.

G2X3.5Y1.75J-2.25

G1Y.25

G2X1.25Y-2.I-2.25

G1G40Y-2.5

G0Z.1

(FINISH WALL STEP 2)

Y3.75

G1Z-.5

G41D51Y3.25

G2X2.75Y1.75J-1.5

G1Y.25

G2X1.25Y-1.25I-1.5

G1G40Y-1.75

G0Z.1

(FINISH WALL)

Y3.

G1Z-.5

G41D51Y2.5

G2X2.Y1.75J-.75

G1Y.25

G2X1.25Y-.5I-.75

G1G40Y-1.

G0Z.1M9

G91G28Z0M19

M1

N2(5/8 SPOT DRILL TOOL )

(1/2-13)

T2M6

M1

N200G0G90G54X.75Y1.S2500M3

G43H2Z.1M8T3

G98G81Z-.25R.1F10.

(.375 DIAMETER)

X2.5Z-.6875R-.4

G80Z.1M9

G91G28Z0M19

M1

N3( 27/64 DRILL TOOL)

(1/2-13 DRILL)

T3M6

M1

N300G0G90G54X.75Y1.S2264M3

G43H3Z.1M8T4

G98G83Z-1.2267R.1Q.2109F9.

G80Z.1M9

G91G28Z0M19

M1

N4(1/2-13 CUT TAPRH TOOL )

T4M6

M1

N400G0G90G54X.75Y1.S130M3

G43H4Z.1M8T5

G84Z-1.35R.1F10.

G80Z.1M9

G91G28Z0M19

M1

N5( #U DRILL TOOL, .368)

(.375 DRILL)

T5M6

M1

N500G0G90G54X2.5Y1.S2595M3

G43H5Z.1M8T6

G98G83Z-1.2106R-

.4Q.184F10.4

G80Z.1M9

G91G28Z0M19

M1

N6(.375 REAMER TOOL, .375)

(.375 REAM)

T6M6

M1

N600G0G90G54X2.5Y1.S1000M3

G43H6Z.1M8T1

G98G85Z-1.2R-.4F10.

G80Z.1M9

G91G28Z0M19

G28Y0

M30

%

References: 3 gen. [112-114]

Assessing questions:

1. What is G code?

2. How to create 3D drawing?

3. How to make programming?

4. What are features of programming?

5. Why it is necessary to know G code?

Practical work № 6

Title: Manufacturing project (on CNC machine).

By using drawings in practical work #1 and #3 create parts on Tormach PCNC 1100 mill.

References: 1 gen. [12-18]

Assessing questions:

1. How to create 3D drawings?

2. How put 3D drawing in to the mill interface?

3. What is G - code?

4. Tools used in the process?

5. How can be planned hole project?