Creo 3.0 G-code Tutorial - IRobotics

Creo 3.0 G-code TutorialIroboticsµTan(Clan)

Table of Contents1.Preface . 22.CAD. 3A.Prepare the CAD. 3B.Define the Coordinate System . 3C.Save the CAD . 63.Create NC assembly . 6A.Create File . 6B.Place reference model . 7C.Create Mill . 8D.Create Operation . 114.Drilling . 13A.5.Standard Drilling / Pecking . 13Roughing . 18A.Roughing . 18B.Volume Roughing . 22C.Profile Milling . 29D.Trajectory Milling . 33E.Finishing . 376.Export the G-Code. 39A.Single Operation . 39B.Multiple Operation . 441

1. PrefaceThis guide is written to help creating g-code file (.tap file) using Creo 3.0 NC machiningextension. This feature is not included in Creo student version. In the guide, couple of basic 3-axisNC/CNC sequences are introduced, but choosing appropriate operation is completely depend on userpreference and design. Brief explanation of each operations are included.Before reading this guide or using CNC machine, I suggest you to go over how much you knowabout 3-axis milling operation, such as what you can do with 3-axis mill, how to calculate adequate RPMor IPM feed-rate, what tool should be used for application, how to set zero, how to maintain or operatethe machine, etc. I am writing the guide assuming you know how to do these.If you have any problem question, or suggestion, feel free to contact me.skim449@illinois.edu2

2. CADA. Prepare the CADIt can be made in Creo 3.0, or imported in .step/.stp file.B. Define the Coordinate SystemIt is generally recommended to use upper left corner of the part as the origin. Click the top surface3

Drag the two green circlesto reference top and left surface.Set the offsets to zero4

Go to orientation tap, and flip/change the coordinate so that the part fits inpositive-x and negative-y.5

Click Ok (middle button on the mouse)Change the coordinate name to G54Note: G54 to G59 is work coordinate system in G-code.C. Save the CADSave the CAD to .prt file, which is the default file extension for Creo part file.3. Create NC assemblyA. Create FileNew Manufacturing NC assembly6

Note: This feature is not included in Creo student version. It only work on EWScomputer.Note: Default template uses inches.B. Place reference modelClick ‘Reference Model’ open the part file place it (use default or fix option)7

or click OkC. Create MillCheck the Number of Axes to be 3Set the tools – go to tool tab tools 8

1. Create the list of toolsa. Type name Select Type Enter the dimension of the tool9

b. Must enter the diameter of the blade. (usually, this is onlydimension needed)i. Length of the blade and tool is unnecessary, if theoperation is single tool operation.ii. If the operation is multi-tool operation, the length ofthe tool is necessary to adjust z-coordinate.c. Click ‘Apply’ to add on the tool list2. After adding the tools, click OkSet the maximum RPM – go to parameters tab type the number(This step is optional, but good practice for safety. Personally recommend for 5000RPM max.)10

Click OkD. Create OperationSelect the Mill you just created (default - MILL01)Set G54 as the Coordinate – expand the part file in the model tree Click G5411

Set the default clearance – Open ‘Clearance Tab’ set the type as plane Selectthe top surface set Value (between 0.15 and 0.5 is usually enough)12

Click Ok4. DrillingDrilling is operation to cut or enlarge the hole. It consist of only vertical movement(z-axis), and moving in other xy-plane direction is forbidden. It is important to find the rightrotation speed (RPM) for the operation, which depend on the diameter of the tool, materialof the tool, material of the stock, and feed-rate.A. Standard Drilling / PeckingGo to Mill tabSelect Standard or PeckingNote: Standard drilling is single motion drilling through the depth, and pecking hasmultiple motion to remove chips as it drill. Pecking is recommended if the materialis thick (generally pecking is used when drilling the depth more than twice thediameter of the drill bit).Select the toolClick holes or multiple holes13

Set Parameters – Go to parameters tab clickto see the detail of parameter.14

Note: All the feed rate is in IPM (inches per minute), distance is in inch, and spindlespeed is in RPM.i. Cut Feed – Speed in Z. For drill bit, IPR (inches per revolution) can be found inthe table. (it depend on the material and diameter of the drill bit) Feed rate RPM x IPRI used 7 – 10 IPM when using ¼ inch drill bit to drill aluminum 6061.ii. Free Feed – The traveling speed in X and Y. It is not mandatory to fill (if it is leftempty, the default value is equal to the Cut Feed), but it is recommended toput value to reduce the total operation time. Generally, number between 35-45is enough.iii. Peck Depth – Only appears for pecking. It depends on the chip clearance andcoolant delivery. Usually, 1.5 to 3 times the diameter of the tool is used.iv. Clear Distance – Clear distance above the surface. If the number is large, it willtake longer time to retract the tool. If the number is too small, the tool mightcontact the surface while traveling. (0.15 – 0.3 is recommended for flat surface)v. Pullout Distance – Distance above the top surface when traveling in X and Y. Ifthe value is not given, default is Clear Distance.15

vi. Spindle Speed – Tool RPM. Use table or other reference to determine thisnumber. Usually, running too slow RPM is major cause of breaking tool,especially when cutting soft (relatively) material like aluminum. It depend onthe material of the drill bit, material of the cutting part, and the diameter of thetool.(Standard Parameters)(Pecking Parameters)vii. Click OKviii. Note: By clicking, these parameters can be reused when creating otheroperation.ix. Note: In the process tab, you can calculate the operation time. The number ismeaningless in terms of unit, because every CNC or NC machine has slightlydifferent running speed. However, the number can be used to compare withother operations. In my experience, the actual operation time takes 2 to 4 timesthe calculated time in minute.16

Click Ok to create drilling operation.Play the path and check17

5. RoughingA. RoughingRoughing operation is used to remove the excess material from the stock androughly cut to the final shape. In general, the result of roughing cut is not very accurate, sofinishing operation is recommended after roughing. (When roughing any large hole, thesize of the hole is slightly smaller than the actual size, which can be used for press-fit thebearing.) In Creo, this sequence uses Mill Window, and try to remove any material that isnot projected by the specified window.The roughing operation requires Mill Window.a) Click Mill Windowb) Click the top surfacec) If necessary, specify the depth18

d) Click OkSelect RoughingSelect the toolSelect References – go to ‘References’ page Select Mill Window in model treeSet Parameters (for detail, click)19

1. Cut Feed – Cutting speed. It depend on material, RPM, and diameter.For aluminum 6061, 10-16 IPM was used for 3/8 inch end milloperation.2. Free Feed / Retract Feed – They are not required but recommended toreduce operation time. In general, machine in ESPL can handle about35-45 IPM.3. Step Over – 1/3 of the diameter of the tool or less is generallyrecommended.4. Max Step Depth – It depend on the material of the tool and number offlute. The operation time largely depend on this parameter20

Click Ok to create operationPlay the path to check21

B. Volume RoughingVolume roughing is used for same purpose as ‘Roughing,’ but it uses Mill Volumeinstead. Simply, it creates the path to remove the mill volume as much as possible. It issimple and easy to use, so it is recommended for general purpose machining.Volume Roughing uses Mill Volumea. Create a volume using extrude, revolve, sweep, or other operation.(I just used extrude to create rectangular cylinder. The size does not matter as long as itcovers all the features, but the height should be the height of the referenced model.)b. Trim the volume using referenced model – Click ‘Trim’ Click Referenced Model (not the mill volume)22

modify using extrude or other tools to remove unnecessary volumes23

c. Click OkNote: To redefine or edit the mill volume, right-click the extrude and click‘redefine mill volume’Click Volume RoughSelect the ToolSelect reference – Go to ‘Reference’ tab click ‘Select items’ Click Mill Volume on the screen24

(Make sure, Machining Reference start with ‘Quilt’)(If it is set to extrude, left-click and remove the reference and click the millvolume on the screen)Set Parameters25

1. Cut Feed – Cutting speed. It depend on material, RPM, and diameter.For aluminum 6061, 10-16 IPM was used for 3/8 inch end milloperation.2. Arc Feed – If the value is not given, default is Cut Feed.3. Free Feed / Retract Feed / Traverse Feed – They are not required butrecommended to reduce operation time. In general, machine in ESPLcan handle about 35-45 IPM.Plunge Feed – The rate of plunging tool into the material. It depend onthe material, material of the tool, and the number of flute. In general, itis lower than Cut Feed.4. Step Over – 1/3 of the diameter of the tool or less is generallyrecommended.5. Max Step Depth – It depend on the material of the tool and number offlute. The operation time largely depend on this parameterClick Ok.Play the path and check26

Note: The path is more visible if you hide the mill volume.27

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C. Profile MillingProfile milling is generally used to create outer shape/profile from the stockmaterial. When using this operation, you should be careful on the set-up and the path, sothat the tool does not run into the vice or the platform. This operation is great to createlarge hole, enlarge any hole, or profile inner arc/shape.Click Profile MillingSelect the toolSelect the reference surfacesCtrl – Click multiple surfacesSet Parameters29

1. Cut Feed – Cutting speed. It depend on material, RPM, and diameter.For aluminum 6061, 10-16 IPM was used for 3/8 inch end milloperation.2. Arc Feed – If the value is not given, default is Cut Feed.3. Free Feed / Retract Feed – They are not required but recommended toreduce operation time. In general, machine in ESPL can handle about35-45 IPM.Plunge Feed – The rate of plunging tool into the material. It depend onthe material, material of the tool, and the number of flute. In general, itis lower than Cut Feed.4. Step Depth – It depend on the material of the tool and number of flute.The operation time largely depend on this parameterClick OkPlay the path and check30

(In general, the above operation is impossible since the piece must be held by thevice, but the tool will run into the vice. In real application, you must set the depth andmake a space for vice grip.)Note: When selecting the reference, it is possible to select boundary by usingshift when clicking the surface.31

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D. Trajectory MillingTrajectory milling simply create a path along the chosen trajectory. In this guide,trajectory milling does not cut/remove any material, but it can be generally used to createchamfer or round feature.Click Trajectory MillingSelect the toolSet ParametersClick the top surface of the partSelect Tool Motionsa. Go to Tool Motion tabb. Click the type of cut (Curve Cut, Drive Surface Cut, Follow Curve)(example is Curve Cut)33

c. Select the trajectoryd. To make a chain, click detaile. Using Ctrl, click chain of trajectory34

6. Click Okf.To add more trajectory, click ‘insert here,’ and repeatg. Click OkPlay the path and check35

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