CAD/CAM C-Hook Technology Slashes Production Time, Eliminates Scrap
Southeast Texas machine shop Houston Mold & Tool, Inc. receives most of its incoming business from the oil and gas industry. Though based in a town named Humble, the six-man shop earned bragging rights for its efficient production of rugged, carbon-steel calibration blocks for oil pipelines.
Mill, Lathe, Wire, Multiaxis
Tool & Die, Energy
“We use 5-axis CNC machining centers to produce calibration blocks for offshore and land pipeline, whether they are for a rig out in the Gulf of Mexico or a large land job,” said Jeff Stott, Owner of Houston Mold & Tool, Inc.
The blocks are used for nondestructive testing (NDT) and evaluation of pipeline flaws and cracks. After pipelines are welded and placed underground or offshore, a scanner on the pipe exterior sends ultrasonic sound beams and examines the weld, testing it for flaws. Houston Mold & Tool’s calibration blocks are used for the setup of scanners, simulating the bevel shape of the pipe before it is welded. The application can get tricky as not all pipes are in pristine condition.
“The pipe is always twisted or warped,” said Stott. “If you have a 48-inch diameter pipe, the spot you might be machining could be 47 inches in diameter because it is twisted. So, I made my own software that probes the pipe, figures out where it is, and takes the theoretical position and moves it to the pipe automatically using the software. Once I run it and save it in our program, it produces a data sheet that we bring into Mastercam.”
Houston Mold & Tool used to machine calibration blocks by hand using jigs. However, the process proved tedious and inaccurate, leading Stott to develop his own CNC program for the application. He spent several years of trial and error perfecting his programming in Microsoft Visual Basic Script. Eventually, he integrated his program into Mastercam, but as versions of the CAD/CAM software progressed, the VBScript application was no longer usable.
In 2005, Stott sought help from Mick George, Senior Software Engineer at Mastercam, to help automate the lengthy programming process for calibration blocks. Together, the colleagues developed a C-Hook, a utility program designed to extend Mastercam.
C-Hooks function as apps for the CAD/CAM software. Mastercam includes an extensive library of C-Hooks. The C-Hook developed specifically for Houston Mold’s calibration block application yields huge time savings. A typical block might have 26 holes per side and four operations for each hole. For each operation, the programmer must set the top of stock, depth, and choose a tool. The C-Hook simplifies the process by importing all geometry and operations, including overrides, speeds, feeds, and depths.
When Houston Mold & Tool receives raw pipe from the field that is slated for placement offshore or on land, the C-Hook imports the job file, geometry, and operations. Once a data sheet is imported, the programmer simply clicks on it. The C-Hook sets all heights, polarizes depths, and chooses tools. The programmer is then able to put all numbers on the print that is supplied to clients on an Excel spreadsheet. The C-Hook takes those numbers and creates a 3D model. Corresponding toolpaths are uploaded, providing everything an operator needs to program the part. The software utility regenerates all hole operations, deletes duplicate lines, and regenerates all operations.
“All our operators have to do is confirm that the data came in correctly,” said Josh Bennatt, Houston Mold & Tool General Manager. “Because there are so many holes and features on a calibration block, to program it and set all the toolpaths would take at least 8 to 10 hours per block. With the C-Hook, Mastercam completes the programming in seconds.”
Depending on customer specifications, each calibration block differs regarding pipe diameter, wall thickness, number of holes, and hole size; therefore, C-hooks vary. Some customers design calibration blocks in three pieces, others use one or two blocks. Pipe thickness varies as well.
When Houston Mold purchased Mastercam 2021, programmers discovered a change in the way 5-axis holes were generated, rendering Houston Mold’s VB files unusable. Stott contacted Bo Rohde, Applications Expert at Mastercam Reseller, MLC CAD Systems, Houston, TX, to help solve the dilemma.
“Bo and his team at MLC CAD Systems worked with us and created a new C-Hook which can import vector lines and operations,” said Stott.
Thanks to the CAD/CAM software and C-Hook technology, Houston Mold & Tool is saving at least six hours of programming time per calibration block. Since using Mastercam for calibration block production, Bennatt says he has never had a scrapped piece.
“If a programmer had to go in there manually, it would be an overwhelming amount of work. Not only that, but he would also have to pick all the vector lines to generate the 5-axis toolpath, then regenerate it.”—Jeff Stott, Owner, Houston Mold & Tool, Inc., Humble, Texas
Machining calibration blocks by using hand jigs proved costly and inaccurate.
Using Mastercam C-Hook technology to automate machining, eliminate redundancies, and cut programming time.
- C-Hook technology saves programming time and eliminates scrap.
- The software utility regenerates all hole operations and regenerates operations.