CNC Manual Programming - Advantages and Disadvantages of Using CNC - Assignment Example

CNC Manual Programming Name: Registration no: University: Course: Code: Lecturer: Introduction CNC programming involves use of instructions that have been listed waiting execution in the written order and procedure. CNC machine codes are always written in block format, meaning that they are read from left to right and from top to down. However, for every code/sentence in a CNC program, it must be written in a separate line. For safety purposes, the block are organized in such a manner that they appear in a sequential manner that promotes readability and predictability. Thus, it is important to follow the standard CNC code structure (Overby, 2010, 76). Basic block arrangement for block must follow this order, program start up, tool loading, turning on the spindle, tuning the coolant on rapid position of the part, machine operation start, stopping the coolant, turning off the spindle, moving to the safe position and lastly ending the program. This procedure is only for a single tool for a single operation. For a program that requires to use different tools the program has to be stopped. Most manufacturing industries use computer numerical control for different functions including shaping of machines. CNC machining covers the gap between what the humans cannot make using bare hand tools since accuracy and consistency is important in the designs. Additionally, using CNC machines tends to be safer than using manual hand tools. Therefore, this report focuses on the use of CNC machine to make the desired designs for engineering systems. However, it is a requirement for this report to do manual CNC coding to ensure that we have proper understanding on the requirements for CNC programming (Smid, 2003, 77). CNC machine tools are usually enclosed completely, which lowers the risk for injury to the operator due to flying debris and chips from broken tools. Safety for CNC machines Always wear eye protective (safety glasses); Never lean on bench with cut chips; Always wear closed shoes when operating the CNC machines (safety boot); Never try to change the tool when the machine is running; Always use a coolant when using a CNC machine; Always switch off the power when the machine is not in use; and Always clean the work place after using the machine to remove the debris and cut chips from the workplace. Objectives Doing the manual CNC coding, the students will be able to understand CNC programming in detail. Manual programming is aimed at helping the student to internalize the detailed CNC coding and be able to interpret different coding. Understanding CNC programming aimed at helping students not to solely rely on computer generated coding and give them proper understanding on how the system works. Advantages of using CNC CNC machine can operate continuously without overheating and they can only be switched off for occasional maintenance; CNC machines manufacture designs that are consistent; Unlike manual lathes, CNC can be operated by less trained operators; CNC improvement requires only software updating to make new designs; CNC training is through a virtual software which is similar to computer game and anyone can learn it from computer screen; Many CNC machines can be supervised by a single individual once programming has been done; Disadvantages The CNC machines are very expensive compared to other manual lathe machines; Any CNC operator or supervisor will require basic training to skills for operation and maintenance of the machine; Investment in CNC can lead many people to unemployment since the machine requires less operators; and Young engineering students do not have basic skills required in operation of CNC machines since they rarely get detailed machine skills. CNC codes Generally, CNC programs are written in simple file that has ASCII charter text, which is easy to view and edit using any, given text editor. The CNC codes use different alphabets and other special address codes when programming. Most of the codes used in CNC are modal and they will remain executed until stopped or cancelled by the operator stopping code. Other codes are non modal and they only work at that moment command. Most CNC codes are made of the G and M codes that are used in executing most commands. Thus the C codes are referred to as the preparatory codes while the M codes are the miscellaneous words and they provide auxiliary options to the machine such as coolant control and spindle direction control. Operation of CNC When planning to use CNC machine it is important to understand the order in which commands must follow when programming. Failure to follow the procedural coding the machine will not execute the codes accordingly. This would lead to machine making the unwanted/unplanned design (Mattson, 2001, 89). Therefore, it is important to have the steps listed accordingly, identify the controls, start the CNC program on the computer, load the required tools, set the length and fixture offsets, load the coded program on the machine control system, run the machine safely, make all the necessary adjustments and lastly when the machining is done use the correct procedure and shut down the CNC machine safely. Set up and operation Process followed by CNC machine set is as indicated in the figure below: Figure 1: CNC process Explanation Pre-start:- it is important to check the machine if the coolant and oil levels are full prior to starting/ignition of the machine. If unsure of the machine operation procedures, check the maintenance manual. Being sure of the machine operation, check the area and clear any unnecessary piece of equipment and tools. Check the machine air supply if required, check the compressor pressure. Home/start: - having checked the machine switch on the power on the control. Load tools: - using the listed order load the tools in the tool carousel. Question 1 N1 G90 , G71 , G00 M13 X0 Y0 S3000 F200 T312 Z5 N2 G01 X0 Y80 S3000 F200 T312 Z10 N3 G02 X10 Y90 S3000 F200 T312 R10 N4 G01 X45 Y90 S3000 F200 T312 N5 G01 X60 Y70 S3000 F200 T312 N6 G01 X80 Y70 S3000 F200 T312 N7 G02 X90 Y60 S3000 F200 T312 R10 N8 G01 X90 Y50 S3000 F200 T312 N9 G03 X100 Y40 S3000 F200 T312 R10 N10 G01 X105 Y40 S3000 F200 T312 N11 G01 X105 Y10 S3000 F200 T312 N12 G01 X95 Y0 S3000 F200 T312 R10 N13 G01 M09 X0 Y0 S3000 F200 T312 N13 G01 M05 X0 Y0 S2000 F300 T28 N14 G01 M06 X0 Y0 S2000 F300 T28 N15 G02 M03 X15 Y60 S2000 F300 T28 N16 G01 M13 X15 Y30 S2000 F300 T28 Z10 N17 G01 M05 X0 Y0 S3000 F200 T28 Z-10 N18 G02 M13 X30 Y15 S3000 F200 T28 Z10 N19 G02 X70 Y15 S3000 F200 T28 Z10 N20 G01 M09 X0 Y0 S3000 F200 T28 Z-10 N21 G01 M05 X0 Y0 S3000 F200 T28 Z-10 N22 G01 M06 X0 Y0 S5000 F400 T18 N23 G02 M13 X30 Y30 S5000 F400 T18 Z15 N24 G02 X30 Y30 S5000 F400 T18 Z-15 N25 G02 X30 Y60 S5000 F400 T18 Z15 N26 G02 X30 Y60 S5000 F400 T18 Z-15 N27 G02 X70 Y60 S5000 F400 T18 Z15 N28 G02 X70 Y60 S5000 F400 T18 Z-15 N29 G02 X70 Y30 S5000 F400 T18 Z15 N30 G02 X70 Y30 S5000 F400 T18 Z-15 N31 G00 X0 Y0 S0 F0 T0 Z0 Explanation N1 G00) Point to point positing, To run the machine (, rapid traverse , G90) To get specific absolute dimension because from the origin point , (G71) and the dimensions in metric units .(M13) start the spindle and coolant together N2 (G01) for linear interpolation to start the profiling, drilling point X fixed to 0 mm , and Y at 80 mm , (S) speed 3000 Rev/Min , (F) Feed rate 200 mm/min and the depth is 10 mm N3 G02 to do the radius, then move X to 10mm and Y to 90 mm maintaining the other settings N4 Change to G01 moving linearly across the compound with X= 45 mm and Y=90 mm N5 Different X = 60mm and Y = 70 mm maintaining the same settings N6 Change the X to 80mm then fix the Y axis at 70 mm N7 Moved X to 90mm, then Y to 60 mm making R10 changing to G02 for curves R10 N8 Move X axis to 90mm and Y to 50 mm N9 Change to G03 circular interpolation motion (CCW) with R10 and changing X to 100mm and the X to 40mm N10 Move to G01 for linear interpolation , fixing Y to 40 mm and X to 105 mm N11 Fixed the X axis at 105 mm and Y to 10 mm N12 Change the setting to G02 for the final curve on the profiling with R10 , X=95 mm and Y=0 mm N13 Maintaining G01 and using M09 to turn off the coolant and withdrawing the tool from the component N14 Stop the spindle with M05 N15 Changing tool with M03 setting to speed 2000 rpm , feed rate 300 and the tool to T28 for slotting at a depth of 10mm N16 Run spindle along the work peace slot at X15 mm and Y30 mm , and turn the coolant off and withdrawing spindle from the work peace N17 Return to origin point (0,0) turning spindle off N18 For the 2nd slot, we turn spindle and the coolant on at X=30mm and y = 15mm N19 Moving along the x axis with 70 mm and Y axis fixed N20 Turn off the coolant and raise the spindle from the working peace N21 Turn off the spindle N22 Tool change (M06) with T18 tool , speed 5000 rev/min , Feed rate with 400 mm/min N23 Maintaining the setting to do the 1st hole at X and Y = 30 mm with depth of 15 mm N24 Raise the tool from the work piece, move it freely to the other holes N25 Maintain the same settings to the 2nd hole at X =30 and Y = 60 mm with depth of 15 mm N26 Raise the tool from the work piece to move it freely to the other holes N27 Maintaining the setting to do the 3rd hole at X =70 and Y = 60 mm with depth of 15 mm N28 Raise the tool from the work piece to move it freely to the other holes N29 Maintaining the setting to do the 4th hole at X =70 and Y = 30 mm with depth of 15 mm N30 Raise the tool from the work piece to finish machining N31 Switch off the CNC machine using 00 in front of the all letters Question 2: N1 G90 , G71 , G00 M13 X0 Y0 S3500 F100 T18 Z5 N2 G01 X-20 Y20 S3500 F100 T18 Z-10 N3 G01 X-20 Y20 S3500 F100 T18 Z10 N4 G01 X-29.80 Y39.80 S3500 F100 T18 Z-10 N5 G01 X-29.80 Y39.80 S3500 F100 T18 Z10 N6 G01 M09 X0 Y0 S3500 F100 T18 N7 G01 M05 X0 Y0 S0 F0 T18 N8 G01 M06 X0 Y0 S0 F0 T38 N9 G01 M13 X-90 Y0 S2000 F150 T38 N10 G01 X0 Y100 S2000 F150 T38 N11 G02 X-40 Y100 S2000 F150 T3 R40 N12 G02 X-70 Y60 S2000 F150 T38 R30 N13 G02 X-90 Y20 S2000 F150 T38 R20 N14 G00 M00 X0 Y0 S0 F0 T3 Explanation N1 G00) Point to point positing, To run the machine (, rapid traverse , G90) To get specific absolute dimension because from the origin point , (G71) and the dimensions in metric units .(M13) start the spindle and coolant together  N2 For linear interpolation used (G01) moving X going to opposite direction and its move 20mm , then Y to 20mm , giving (S) speed 3500 Rev/Min , (F) Feed rate 100 mm/min. to drill hole one. N3 Raise the tool 10mm up off the work piece and move to the next hole N4 Repeat the same procedure but change X to 29.80mm and Y to 39.80mm to drill the 2nd hole N5 Lift the tool 10mm up from the work piece and move it freely  N6 Re-set to another command and (M09) to switch off the coolant N7 Turn of the spindle for tool change N8 Changes to T38 N9 Coolant and spindle (M13) turned on with X=-90 mm with Y=0 mm , with new speed, S = 2000 rev/min and feed rate of 150 mm/min  N10 (G01) for linear operation, moving X=0 mm and Y=100 to do the Y line on the Y axis N11 Used (G02) for circular interpolation to do the curves and (M06) to change the tool that we used to T38 then shifting X= 40mm and Y=100 mm to do the curve the radius is 40 mm  N12 Maintain the setting but move X = -70mm and Y=60mm with R=30  N13 Maintain the setting but move to X= -90mm and Y=20 mm to do the curve the radius is 20 mm  N14 Maintain the setting but move to X= 90 mm and Y=20 mm to do the curve the radius is 20 mm Qestion3 N1 G90 , G71 , G00 M13 X0 Y0 S2600 F180 T36 Z-5 N2 G01 X12 Y12 S2600 F180 T36 Z-10 N3 G01 X82 Y12 S2600 F180 T36 N4 G01 X82 Y0 S2600 F180 T36 N5 G01 X102 Y0 S2600 F180 T36 N6 G06 X102 Y35 S2600 F180 T36 R10 N7 G01 X102 Y45 S2600 F180 T36 N8 G01 M05 X102 Y45 S2600 F180 T36 Z10 N9 G03 M04 X77 Y70 S2600 F180 T36 Z-10 R25 N10 G01 M05 X0 Y0 S2600 F180 T36 Z10 N11 G01 M03 X0 Y25 S2600 F180 T36 Z-10 N12 G01 M09 X77 Y45 S2600 F180 T36 N13 G01 M05 X77 Y45 S2600 F180 T36 Z10 N14 G01 M06 X0 Y0 S0 F0 T110 N15 G01 M13 X51 Y25 S4500 F160 T110 Z-10 R10 N16 G01 X51 Y25 S4500 F160 T110 Z10 N17 G01 X77 Y45 S4500 F160 T110 Z-10 R10 N18 G01 X77 Y45 S4500 F160 T110 Z10 N19 G00 M00 X0 Y0 S0 F0 T110 Explanation N1 G00) Point to point positing, To run the machine (, rapid traverse , G90) To get specific absolute dimension because from the origin point , (G71) and the dimensions in metric units .(M13) start the spindle and coolant together N2 For Linear interpolation we used (G01) to start the profiling, setting X to 12 mm , then Y moves 12 mm , using (S) speed 2600 Rev/Min , (F) Feed rate 180 mm/min . N3 Changed X to 82mm and Y to 12 mm maintaining the settings to do the rectangular gap in the X axis N4 Then change X = 82mm and Y axis to Zero point to close the rectangular gap N5 Change X=102 mm and Y=0 to close the compound from the X axis N6 Maintaining X=102 mm and changing Y=35 mm , to do a half circle with R10 by applying (G02) N7 Keeping the X dimension and changing Y to 45mm N8 To stop the spindle (M05) raise the Z axis to 10mm moving freely to a new position N9 Run the spindle CCW (M04) at same speed and feed rate changing X = 77 mm and Y = 70 mm and return the depth Z to -10mm, (G03) for circler interpolation motion CCW with R25 N10 Move the spindle to the origin (0,0) and raise the Z to +10 to move freely N11 Move (0,0) to Y=25 mm and x=0 mm, operating the spindle with (M03) CW , with Z-10 depth N12 Move X to 77mm and Y to 45mm turning off the coolant N13 Stopped the spindle, (M05) and shifting Z to 10mm to move freely to any point after touching the work piece. N14 Return to (0,0) and (M06) to change the tool to T110 N15 Tuning the spindle and the coolant on (M13) and changing the speed to 4500 rev/min , feed rate to 160 mm/min , X=51 mm and Y=25 to drill the hole with 10mm depth and R10 N16 Raise spindle from the piece of work to 10mm to move to the next hole N17 Drilling R10 at X to 77mm and Y to 45 mm at a depth of 10mm N18 Raise the tool and shift to (0,0) N19 Switch off the CNC machine by using 00 in front of the all letters Conclusion: Manual tool programming sometimes can be complicated when coding for numerous parts to work on. Thus, in this assignment all the CNC coding has been manually configured to work as per the expected codes in a CNC machine. All the codes used in the programming are explained in tables 1 to 3, below each question respectively. References Overby, A., 2010, CNC Machining Handbook: Building, Programming, and Implementation, McGraw Hill Professional. Mattson, M., 2001, CNC Programming: Principles and Applications, New York, Cengage Learning. Smid, P., 2003, CNC Programming Handbook: A Comprehensive Guide to Practical CNC Programming, New York, Industrial Press Inc. Read More