15-10-2016, 03:10 PM
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A Post Processor is a unique “driver” specific to a CNC machine; some CNC machines start at different locations or require extra movement between each operation, the Post-Processor works with the CAM software to make sure the G-Code output is correct for a specific machine build. Another example of use for a Post-Processor would be an ATC (Automatic-Tool-Change) for a CNC, the Post-Processor is required so the correct Tool is collected from the correct location. The Post Processor controls the format and syntax of the program that is generated for the controller that controls a specific machine (typically a CNC or a robot).[1]
A post processor is commonly used by the CAM (Computer Aided Manufacturing) Software to generate G-code for a specific CNC Machine.
NC machines work by following the commands or instructions (G-codes / M-codes) which are given in Part Program. Here are G-codes for MACH3 CNC control which are necessary for a CNC machinists to learn to understand CNC programming.
Turning Cycle for Straight Turning
G20 longitudinal turning cycle for Fanuc 21 TB cnc control is a modal G-code.G20 turning cycle can be used for straight turning and taper turning as well.G20 turning cycle is Easy to program and learn. G20 turning cycle is used for simple turning however multiple passes are possible by specifying the X-axis location of additional passes.
G20 Turning Cycle Format for Straight Turning
G20 X… Z… F…
G20 U… W… F…
X – Diameter to be cut (absolute).
Z – End point in z-axis (absolute).
F – Feed-rate.
U – Diameter to be cut (incremental).
W – End point in z-axis (incremental).
CNC Program Code Explanation
As you can see in the above cnc program code,
Tool is at X56 Z2 point,
First cut is made at X51 and tool travels W-20 in Z-axis.
Second cut is made at X46
Third cut is made at X41
…
Last cut is made at X30
G20 Turning Cycle Function
As if you study the above cnc program code you will notice that,
1 – with G20 both absolute (X51.0) and incremental (W-20.0) values are used to make cuts.
2 – If above code also shows a very powerful functionality of G20 turning cycle which is that a cnc machinist can control depth-of-cut of every pass of G20 turning cycle which is impossible to achieve with other Turning Canned Cycle like G71 Rough Turning Cycle.
So you will notice first five-cuts are of 5mm deep but the last one is just 1mm deep.
Cancellation of G20 Turning Cycle
G20 turning cycle is a modal G-code.
“Modal” G-code meaning that they stay in effect until they are cancelled or replaced by a contradictory G code.
It means G20 turning cycle remains active until another motion command is given like G00, G01 etc. As in above cnc program example G20 G code is cancelled with G00 G code.
SNAP GAUGE
AIM: To measure the unknown components of fixed dimensions and to sort out the defected one. APPARATUS: Snap gauge, Block Gauges. THEORY: Snap gauge is a form of Go/no go gauge. It is a limit gage with permanently or temporarily fixed measurement aperture(s) (gaps) which is used to quickly verify whether an outside dimension of a part matches a preset dimension or falls within predefined tolerances
A Post Processor is a unique “driver” specific to a CNC machine; some CNC machines start at different locations or require extra movement between each operation, the Post-Processor works with the CAM software to make sure the G-Code output is correct for a specific machine build. Another example of use for a Post-Processor would be an ATC (Automatic-Tool-Change) for a CNC, the Post-Processor is required so the correct Tool is collected from the correct location. The Post Processor controls the format and syntax of the program that is generated for the controller that controls a specific machine (typically a CNC or a robot).[1]
A post processor is commonly used by the CAM (Computer Aided Manufacturing) Software to generate G-code for a specific CNC Machine.
NC machines work by following the commands or instructions (G-codes / M-codes) which are given in Part Program. Here are G-codes for MACH3 CNC control which are necessary for a CNC machinists to learn to understand CNC programming.
Turning Cycle for Straight Turning
G20 longitudinal turning cycle for Fanuc 21 TB cnc control is a modal G-code.G20 turning cycle can be used for straight turning and taper turning as well.G20 turning cycle is Easy to program and learn. G20 turning cycle is used for simple turning however multiple passes are possible by specifying the X-axis location of additional passes.
G20 Turning Cycle Format for Straight Turning
G20 X… Z… F…
G20 U… W… F…
X – Diameter to be cut (absolute).
Z – End point in z-axis (absolute).
F – Feed-rate.
U – Diameter to be cut (incremental).
W – End point in z-axis (incremental).
CNC Program Code Explanation
As you can see in the above cnc program code,
Tool is at X56 Z2 point,
First cut is made at X51 and tool travels W-20 in Z-axis.
Second cut is made at X46
Third cut is made at X41
…
Last cut is made at X30
G20 Turning Cycle Function
As if you study the above cnc program code you will notice that,
1 – with G20 both absolute (X51.0) and incremental (W-20.0) values are used to make cuts.
2 – If above code also shows a very powerful functionality of G20 turning cycle which is that a cnc machinist can control depth-of-cut of every pass of G20 turning cycle which is impossible to achieve with other Turning Canned Cycle like G71 Rough Turning Cycle.
So you will notice first five-cuts are of 5mm deep but the last one is just 1mm deep.
Cancellation of G20 Turning Cycle
G20 turning cycle is a modal G-code.
“Modal” G-code meaning that they stay in effect until they are cancelled or replaced by a contradictory G code.
It means G20 turning cycle remains active until another motion command is given like G00, G01 etc. As in above cnc program example G20 G code is cancelled with G00 G code.
SNAP GAUGE
AIM: To measure the unknown components of fixed dimensions and to sort out the defected one. APPARATUS: Snap gauge, Block Gauges. THEORY: Snap gauge is a form of Go/no go gauge. It is a limit gage with permanently or temporarily fixed measurement aperture(s) (gaps) which is used to quickly verify whether an outside dimension of a part matches a preset dimension or falls within predefined tolerances