Threadtracer for Gibbscam

This guide covers the Acme Screw Thread part of ThreadTracer. .

Preface

This plugin requires some experience in GibbsCAM and general knowledge about threads and how machining a thread works.

While ThreadTracer will provide all the necessary data and calculations to generate a thread based on your input, the end user or operator of the machine tool must provide safe and working cutting data, and tooling that works for threading.

Single Point Threading The prinsiple is simple, by calculating coordinates to form a complete thread profile, most thread styles and types can be machined with a small single tip tool. This enables machining of a variety of threads without special carbide tools.

The main goal of this plugin was to get machining threads faster, by skipping the need for looking up tables or Excel sheets for thread data.

Basic requirements : -GibbsCAM 12.0.45 or newer -Powerful computer and good graphics card. -Moorpark.TTF font installed for textual information as GibbsCAM geometry

Terminology ThreadTracer refers to all the thread data, numbers,words and terminology as described in ANSI and ISO documents for thread standards.

Always be certain that you supply numbers in a correct format, be cautious and be sure not to set TPI for a metric thread or vice versa.

Pitch Conversions

Pitch (in general) - Distance from any point on the thread to the corresponding point in the adjacent thread. TPI - Threads Per Inch

Pitch (imperial) - Distance of 1 revolution of thread in inches. In numerical this is 1/TPI, for a 4-TPI thread this is 1/4 = 0.25 inches To convert metric pitch to TPI in numerical, is 25.4/pitch, for a 8mm metric pitch this is 25.4/8 = 3.175 TPI

Pitch (metric) - Distance of 1 revolution of thread in millimeters. To convert imperial TPI to millimeters, is 25.4/TPI, for a 4-TPI thread this is 25.4/4 = 6.35 millimeters To convert imperial numerical pitch to millimeters, is pitch x 25.4, an 0.25 inch pitch x 25.4 = 6.35 millimeters 02/18

Built in support for ANSI B1.5 - 1997 - ACME Screw threads. Tolerance Class : 2G-3G-4G

The first window is for setting up all the necessary threading data. For Acme threads ThreadTracer accepts the nominal in both inch or metric, and the TPI for the thread. If GibbsCAM is set to inch, enter the Nominal as inch, if GibbsCAM is set to metric, enter the Nominal as millimeters.

After setting the nominal, TPI and tolerance class you must always press the 'Update Thread Data' button to calculate the new numbers.

Nominal- Enterthenominaldiameterofthethread TPI - Enter the TPI of the thread External/Internal Select for external or internal thread

ANSI B1.5 Acme threads have multiple tolerances available, select the desired tolerance class from the dropdown menu, 2G, 3G or 4G

Press the 'Update Thread Data' button to calculate and update the rest of the values to the selected thread size

Note! Always click the 'Update Thread Data' button after changing either nominal, Pitch, any of the tolerance classes or External/Internal thread

All the input boxes and dropdowns under the 'Thread Data' will be used to calculate the Major,Pitch,Minor and the flat root width. These numbers will be displayed in inch if GibbsCam is set to inch mode or displayed in millimeters if GibbsCAM is set to metric mode.

You can change any of these numbers as long as you stay within max and min for Major Diameter and Minor Diameter. By default the Major Diameter and Minor Diameter will be set to the mean value between max and min tolerance. 03/18

After the 'Update Thread Data' button is pressed, the following input boxes have been filled with the new values. Flat Root Width should not be altered to stay within the spesification, but if the threads are to be coated, you can widen the Flat Root Width to compensate for the coating. Only adjust values to between max and min. Crest radius and Root radius are set to half of the maximum allowed from the spesification, but you can adjust these to max to allow a better choice in tooling.

If the thread have multiple starts, select from the 'No. Starts' dropdown. ( GibbsCAM will control the number of starts with its internal threading operation, by offsetting the start Z point by the pitch amount. )

Note! You can NOT generate g-code for multiple starts with the internal NC Tracer post processor,

you have to use the threading operations from GibbsCAM to machine threads with multiple starts. If its a left hand thread, enable the 'Left Hand' checkmark. The tool will then have 'Face Up' set in the GibbsCAM tool setup.

Use the 'lock' checkbox to lock two of the numbers, locking two will result in the third being calculated based on the two locked numbers, eg. Major Diameter locked at 99.841mm and Thread Height locked at 3.5mm and the Minor Diameter will adjust itself to 92.841mm. If you change anything by mistake or clears an input box, you can always press the 'Update Thread Data' and the numbers will be set back to its initial values.

If any numbers that are set over max or under min, an error message will be displayed on screen and a red box will appear on the number thats out of spesification.

When everything is set, press the 'Machining' button to proceed to the machining window. 04/18

The Machining window controls the tool and various roughing and finishing settings.

Tool Parameters Set the width of the tool used for machining the thread. If you can, use a tool that is close to the root portion of the thread profile to avoid unnecessary machining. Set the tool radius in 'Tip rad' (for round inserts, the tip rad will be exactly half the tool width)

Note! As a safety measure, if 'Tip Rad' is set to large compared to the width, it will automaticly be adjusted to half the width. Its important that Tool Width and Tip Rad is as accurate as possible, as both these determine how the thread profile are machined.

A Tip Rad of 0 are generally not accepted, all tools must have atleast a tiny radius. Offset X - See Page 9 and 10 on how this works combined with the 'Material Only' option.

Start Z - Set where the threading will start on your part. End Z - Set where the threading will end on your part.

Start Z should be atleast a distance equal to the pitch of the thread outside the actual part, so the tool always have clearance for when it starts the cut.

End Z should be set closest to the end of the thread relief. If no thread relief are available, set it close to the nearing feature or shoulder.

StepdownXr -Sethowmuchthetoolwillcutforeachpass (DepthofCut,intheXaxisdirection) StepoverZ -Sethowmuchthetoolwillcutforeachpass(DepthofCut,intheZaxisdirections) StockX -Sethowmuchmaterialtoleaveforthefinishingcuts,intheXaxisdirection StockZ -Sethowmuchmaterialtoleaveforthefinishingcuts,intheZaxisdirections

SMPM or SFPM - Set the surface cutting speed for the tool, if GibbsCAM is in metric mode, set as Surface Meters per Minute If GibbsCAM is set to inch mode, set as Surface Feet per Minute. The actual RPM will be calculated based on diameter of the thread, with the surface cutting speed. 05/18

Roughing Strategy

Left to Right - Tool will start on the left side of the thread profile and cut towards the right side, the tool will move the distance set in 'Stepover Z' for each pass. Right to left - Tool will start on the right side of the thread profile and cut towards the left side, the tool will move the distance set in 'Stepover Z' for each pass. Zigzag- Ifenabled,thetoolwillalternatebetweencuttingfromleft->rightandright->left Using zigzag will prevent one side of the tool to be worn out, as both sides will be used between alternating cuts.

Note! Roughing will follow the flank angle and not consider the crest and root radius, if the set tool have a small tip radius compared to the root radius of the thread, the tool might cut into the root radius. Use the on screen geometry and zoom to confirm that the tool stays within the thread profile. If the tool cuts into the root radius of the thread, adjust the 'Stock Z' to leave more material until the tool stays within the thread profile.

Use Adaptive - This option can be used for thread profiles with large crest and root radiuses. The tool will make smaller cuts along the crest and root radius, and will leave equal amount of material for the finishing passes. With Adaptive enabled, the number in 'Stock X' will be used as an outline of the thread profile and the 'Stock Z' input box are disabled and not in use.

Adjust the level of 'adaptiveness' with the radio buttons, buttons towards green will add more cuts and smooth out the radius more, and buttons towards red will do less cuts and radius will me more jagged. When the Crest radius end and the straight flank wall starts, the 'Stepdown Xr' value will be used until the root radius starts, and adaptive cut calculations will start again.

Exaggerated Example Adaptiveoff AdaptiveOn

With 'Adaptive On' the roughing cut amount will increase incrementally along the radius, leaving equal amount of material for the finishing passes. 06/18

Center Out - Will only rough the center of the thread, or the width that equals the flat between root radiuses. The flank angle will not be roughed and can be machined with the finishing passes. This will reduce the amount of roughing cuts but should only be used on light materials, as delrin or composites where tool wear are not a concern.

Process Options

These checkboxes allows for different processing options.

Do Roughing - Calculate roughing passes Do Finishing - Calculate finishing passes along the whole thread profile. The finishing tool will move along the thread profile like 'No Drag' contouring in GibbsCAM.

You can switch on or off these independently, when setting up the machining, just enable roughing and use the visual drawn tool to confirm that everything looks correct. When the roughing looks correct, disable the 'Do Roughing' checkbox and enable the 'Do Finishing' checkbox, and again visually confirm that the finishing passes looks correct.

Target Ra - This is the distance between finishing passes, it calculates the distance based on Ra value entered here. Target Ra of 0.8 produces more cuts than a Target Ra of 1.6. Ranges from Ra 0.1 - 6.3 are supported.

Note! The calculations for Ra is only a theoretical approximation, if a Ra value is spesified as a critical requirement, use designated measuring equipment to confirm the actual surface Ra. Additional tool wear and shatter will always impact surface roughness. Finish Flats - Calculate finishing passes over the top of the thread, use this if you want the same tool to machine all parts of the thread, leaving this off will only machine starting from the crest radius and follow the thread profile. There is always an advantage to having the same tool machine the Major and Minor diameter, its suggested to always enable 'Finish Flats'.

Process Ops - When selected, it will generate threading operations in the current GibbsCAM part, only enable this when both roughing and finishing passes have been set up. It also creates the tool based on parameters under 'Tool Parameters'. You need to edit this after the threading operations have been made, set the correct tool number and tool offset as in the machine.

NC Tracer ISO - This uses an internal post processor, no GibbsCAM operations will be generated. See Page 13-14-15 and 16 for details on how to use NC Tracer 07/18

Visual Geometry

These checkboxes allows for different visual geometry creation.

Draw Points - Draws a yellow point for each tool coordinate ( point where tool presetter touches tool in X/Z )

Draw Full Tool - Draws geometry representing the full size configured tool for each cut. Helpful as a visual confirmation that the tool moves correctly between each cut.

Keep Tool - When enabled will keep the geometry for the tool on screen. When disabled will delete each tool geometry before drawing the next cut.

Textual Info - Used the engrave tool in GibbsCAM to write dimensional info beside the thread profile.

Full Thrd Profile - Will draw a loop of the thread profile between the Start Z and End Z Saving the current ThreadTracer project

Save - When enabled, will store all current set thread and machine parameters into the GibbsCAM partfile when you press theDo ' It' button, the plugin will automaticly restart. Opening the GibbsCAM program 3 months later and running the plugin will allow loading back all the previous settings into the plugin and redo the thread, or change cut depth on the same thread. Update - If the thread data are already loaded from the GibbsCAM partfile, the label will change to Update. Enable the 'Update' and press 'Do It' to update and rewrite the new thread data inside the GibbsCAM part. Note1! If 'Save' or 'Update' checkmark is selected, the 'Do It' button will only save or update the current thread data into the open .vnc file, no thread calculations are performed. Note2! Remember to save the GibbsCAM part file itself, to permanently save the ThreadTracer data.

Saved data will be added as comments under, Document Control -> Comments -> Programmer Notes You can store as many thread setups as you like. The data here contains everything to set up the plugin to the same state for the settings as when you saved it. This way you can load back a custom thread and setup and just alter for example cut depth, or surface cutting speed and redo the threading operations. 08/18

Loading back a ThreadTracer project

To load back ThreadTracer setups that you previous have saved, just start ThreadTracer after you loaded the GibbsCAM .vnc file. ThreadTracer will then present a dropdown menu, containing all the saved threads that you can select.

Operation Procedure

Everything in the machining window is controlled by the' Do It' button. You can turn on/off options, generate visual geometry, change cut depths, change tool sizes and everything will be recalculated and updated when you press'Do It'. As long as the 'Process Ops' or 'NC Tracer ISO' are disabled, no cuts or g-code will be generated.

Set up the thread and enable 'Process Ops' when everything seems correct. CAUTION ! All threading clearances are taken from within GibbsCAM -> 'Auto Clearance'. So with auto clearance set to 1mm, the tool will do all rapid moves 1mm from the Major diameter on external threads, and 1mm below the Minor Diameter on internal threads. Keep this in mind when setting up INTERNAL threads, and the size of your tooling compared to clearance.

Yellow dots represents the acutal tool tip coordinates Enable 'Draw Tool' too see the acual size tool

'Text Info' writes technical thread information onscreen View the finishing cuts seperate from roughing cuts 09/18

Use GibbsCAM Op Sim, to simulate material removal and verify that the threading operations produce the desired part without gouges or clashes.

Post all the operations with your well-known GibbsCAM post processor. 10/18

Using different size tools for roughing.

If its desired to use multiple tools for roughing, you can do this with the 'Offset X' When a tool is too large for reach the full depth of the thread, it will be stopped when it reach the boundaries of the thread profile and the set stock. The 'Offset X' input box will then hold the X axis value of how far it could machine. So for example, with a tool thats too large and the roughing calculations stops the tool after 1.229mm from the Major Diameter, the 'Offset X' will be automaticly set to '1.229'

Then its possible to enter a smaller tool, that fits inside the thread profile, and enable the 'Materal Only' checkbox. The roughing calculations will then start at this X value, continuing the cuts intil it reaches the root of the thread.

Remember that you need to first enable 'Process Ops' and let GibbsCAM generate the threading operations for the first tool that didnt reached the root, then use a smaller tool and enable 'Materal Only', and again enable 'Process Ops' and get GibbsCAM generate the rest of the roughing passes with a second tool.

ThreadTracer will always make and use a new tool, everytime you change tool width or tool tip radius. Note! As long as 'Materal Only' is enabled, any roughing with any sized tool will start from the X height in the 'Offset X' input box.

Example A TR100 with 6mm pitch have a flat root of 1.926mm, so we need a tool smaller than 1.9mm If a 3mm tool is used first, the roughing calculations will go as far as the tool can reach.

Here the 3mm tool stops at 1.229mm measured from the Major Diameter. The 'Offset X' will hold this number. Then by setting a smaller tool, and enabling 'Material Only', the new tool will continue from where the last tool stopped. It will start roughing 1.229mm from the Major Diameter + the 'Stepdown Xr' value.

This tool of 2mm still didnt reach the root of the thread, and the 'Offset X' have been updated with the new machined depth. 11/18

By setting the final tool to 1mm width, the roughing is complete.

To machine a thread using multiple roughing tools, you need to enable 'Process Ops' for each tool and let ThreadTracer generate the GibbsCAM threading operations for each tool. Remember to edit each tool before you post the program, and set the correct tool number and tool offset.

There will be created seperate Workgroups for all the different Roughing stages, for this example there was three seperate Workgroups created, that show the different tool sizes used for roughing. Workgroup 7-8-9 will hold the geometry and tool coordinates so its easy to switch between them to confirm that the next tool will start to cut at the correct X depth. 12/18

Blunt Start / Higbee Cut

ThreadTracer supports threading a blunt start or Higbee Cut. This will remove the incomplete thread at the start of the thread where the tool enters the material. A blunt start have several advantages and will help prevent crossthreading and serves as an easy identifier for where the first thread starts. Its preferable to apply a blunt start on threaded part that are repeatedly assembled.

There are several parameters to adjust, but as default its pre configured conservatily.

BluntStepdownXr- Sethowmuchthetoolwillcutforeachpass,intheXaxis BluntStepoverZ - Sethowmuchthetoolwillcutforeachpass,intheZaxis By default these two input boxes are set to the same as Stepdown Xr and Stepover Z used in roughing Uncheck any of the checkboxes next to the input box to set a seperate value.

Blunt Distance - Set how many revolutions of thread to cut before applying the Blunt Start. By default its set to 2 revolutions, the first revolution is mostly air so there will be approximately one revolution of thread removed before the tool exits the thread. Blunt Distance can be any number with decimal, so 2.5 will remove 2.5 revolutions of threads and exit out of the thread (1.5 of actual thread on the part)

Blunt Spindle RPM -Select 100% or 50%, of the value set as SMPM/SFPM for the threading operation This can be used in combination with 'Blunt Exit Cut' set to 'Rapid Exit' to cut a very short Blunt Start.

Run Out Angle - Set the run out angle for the tool, 0 degrees is straight up on external threads and straight down on internal threads. Its normal to keep this between 0 and 10, higher number makes a longer length on the blunt, as the tool needs to move a longer path to exit the thread. Its set as 5 degrees by default.

Note! 'Run Out Angle' have no effect if the 'Blunt Exit Cut' is set as 'Rapid Exit'

Blunt Offset - Will move the blunting Z coordinates sideways, negative numbers moves all the cuts towards the left and positive numbers move all the cuts towards the right. Use this and do small adjustments if the tool leaves a sharp edge on any side of the thread.

Right Side Trim - Will shorten the cutting movement on the right side of the blunt Left Side Trim - Will shorten the cutting movement on the left side of the blunt

Blunt Exit Cut - Set if the tool will use feed when exiting the thread, feedrate will always be the same as the pitch of the thread. Rapid Exit will make a G0 move out of the cut, this will leave the shortest Blunt Start possible. Rapid exit should be used with care, if your machine tool have adjustable Rapid feed knob, and tool moves slowly out of the thread, it will cut away most of the thread at the Z position as the spindle and tool are not synchronized during G0 moves. Rapid feed should always be used on with Rapid Feed set to 100% 13/18

Blunt Start / Higbee Cut

The Blunt cuts will follow along the flank profile, with less cuts from the crest and increasingly more cuts towards the root.

With the default settings (Blunt Offset=0, both sides Trim=0) the tool will cut slightly past the thread flank walls.

Setting the Blunt Offset to -0.5 will move all the threading Z values for the blunt cuts -0.5mm in the -Z direction

Setting the Left and Right Trim to 0.5 will move or shrink the threading Z movement inward. Produces less cuts

GibbsCAM threading operations for a Blunt start. Run Out Angle set to 5°

GibbsCAM threading operations for a Blunt start. Run Out Angle set to 15° NC Tracer - Gcode PostProcessor 14/18

NC Tracer is a minimal post-processor that enables output of simple Gcode

You can also skip having 100's of threading operations within your main GibbsCAM program, and use NC Tracer to generate the threading cuts, and just add these with 'Add Gcode' after the lathe operations that turns the part ready for threading. Then you can post the whole program with your GibbsCAM post processor, with all the g-code for threading included.

Or use NC Tracer for generating the g-code if your post processor does not support correct output of G32/G33 threading operations. (...) or for use on machines without a GibbsCAM postprocessor.

All gcode processed with NC Tracer will have identical G32/G33 threading coordinates as any GibbsCAM post

It supports upto 10 different machine configurations. Build up settings for any machine by filling in the G and M codes required with the control. Consult your machine manual or machine tool distributor for M or G codes, unless you can pick them up from your GibbsCAM post.

Machine Name - Display name of the configuration inside the dropdown menu and inside the output G-code.

NC Header 6 entries or lines available for setting up things before any threading starts. In this example, the first line selects the upper turret and at the 4th line, max rpm is set with a G50 command NC Tracer - Gcode PostProcessor 15/18

NC Footer 6 entries or lines available for setting up things after the threading The last line should be used for the 'Program Stop' command. All CNC controllers needs this to 'end' the program properly. Usually 'M30' on fanuc compatible controls, most Okuma machines uses 'M2'

Optional Output Optional switches, mostly informational output. 'Insert M1 Stops' will output an 'M1' optional stop after roughing passes are done. 'M1 after every cut' will output an 'M1' optional stop after every single cut.

File Formatting Metric/Inch output are controlled by GibbsCAM in 'Document Control' 'Prepare as 'Add Gcode' will output every line in double quotes, so it can be inserted inside a GibbsCAM program with the plugin 'Add Gcode' Output to Clipboard - Will skip asking your for a file to write to and copy all G-code output to the clipboard, handy to just paste directly into your preferred editor or DNC utility. File Extension - Set file extension for saved files (NFC,EIA,MIN,etc) No.of Decimals - Rounds the X/Z coordinate values to set number of decimals (X32.4446445 becomes X32.4446) Metric machines should use atleast 3, and imperial machines atleast 4

By enabling both 'Prepare as Add Gcode' and 'Output to Clipboard', NC Tracer will automaticly run and open the internal GibbsCAM plugin 'Add Gcode' and then you just hit 'CTRL-V' to paste the Gcode. NC Tracer - Gcode PostProcessor 16/18

G&MCodes All the various G and M codes required to run the thread in the machine tool. ThreadingCycle-The G Code for Single Point Theading. On Fanuc compatible controls its usually G32. Most if not all Okuma controls use G33. Pitch Prefix - The letter used for Pitch in the Single Point Theading cycle. Usually this letter is F. CoolantOn- TheM-CodeforturningONcoolantforthethreadingtool. CoolantOff- TheM-CodeforturningOFFcoolantforthethreadingtool. SpindleRH- TheM-CodeforClockwisespindledirection. Used for Right Hand threads and threading toward the -Z axis SpindleLH- TheM-CodeforCounterClockwisespindledirection. Used for Left Hand threads and threading toward the -Z axis HomeX-The G-Code for Homing the X axis. HomeZ- The G-Code for Homing the Z axis. Operation Prefix - The letter used for sequencing, Fanuc compatible controls uses the letter N, some Okuma controls NAT Its important to configure the correct codes for your machine tool, consult with the distributor of the the machine tool, or find the correct G and M codes from the manuals that came with the machine. Missing or wrong commands could cause damage to the part or to the machine tool.

Any G-code posted with NC Tracer while error messages are displayed, NC Tracer will output a warning on the first line. NC Tracer - Gcode PostProcessor 17/18

The generated Gcode opens automaticly with Notepad when saved normally. Its recommended to inspect the code and verify that the Gcode is correct and that the machine configuration is set up correctly for the machine tool. With comments enabled the code is easily readable, with information on how many cuts total,estimated time to run all the cuts, thread data,etc CAUTION ! All threading clearances are taken from within GibbsCAM -> 'Auto Clearance'. So with auto clearance set to 1mm, the tool will do all rapid moves 1mm from the Major diameter on external threads, and 1mm below the Minor Diameter on internal threads. Keep this in mind when setting up INTERNAL threads, and the size of your tooling compared to clearance.

Tooling

Insert the 'T' command to select the tool used, there is one tool for roughing and one tool for finishing. You cannot edit the tool parameters here, they are the same as you set in ThreadTracer and greyed out. If you want one seperate tool for running finishing cuts with, select the 'Use seperate Finishing' and enter another 'T' command here. If your toolchange command requires and Mcode, you must also include that. An Okuma Multus uses for example 'TD=010001 M323'

Note! If a second tool is used for finishing passes, it *must* be identical as the roughing tool. Use of different size tools are only supported when generating threading operations within GibbsCAM! 18/18

Measure over wire You can use the GibbsCAM geometry to find values for measuring over wire. By using the Geometry Palette, first select the two lines representing the flank of the thread. Then click the Circle, and enter the radius of the wire to be used.

By using calibrated thread inspection equipment for the spesific thread, and a ball contact point you can get accurate measurements and confirm that the flank diameter is within tolerance.