Surfcam Machines to the Max

By Robert Simon and Terry Wohlers

Published in Vol. 13, No. 3, March 1994 issue of Computer-Aided Engineering
Copyright 1994 by Robert Simon and Terry Wohlers

Surfcam is a multiple axis computer-aided manufacturing (CAM) software package designed for 3D surface modeling and CNC machining. The software, which features fast surface rendering for design visualization, is the first CAM package in its class to run in Windows 3.1, 32-bit enhanced mode. This makes Surfcam for Windows significantly faster than the 16-bit DOS version, which is not slow.

The Surfcam software we tested was valued at $18,000, although customers can get started with 21Ú2-axis milling for around $2,500. Overall, we were impressed with the operation and versatility of the software. Even 5-axis machining was straightforward once you learn the terms and procedures. From the first version, Surfcam has used true mathematical surfaces to store and manipulate the model, unlike most other early PC-based surface machining packages.

What's New?

Surfcam supports 3-axis machining of multiple surfaces, including Nurbs, parametric, and composite surfaces using various types of end mills. A composite surface consists of two or more surfaces trimmed and linked together, permitting you to machine multiple surfaces as one. Composite surfaces eliminate the need to produce separate NC programs for every surface, thus reducing the amount of time needed to generate the NC program. Machining time is reduced also. Without composite surfaces, you must program and machine every surface separately.

New to both the DOS and Windows versions is plotter support, including drivers for several popular formats such as HPGL, HPGL/2, CalComp, and DMPL. Several 3D design and surface editing features and a lathe machining module have been added also. Extensive additions include complete tool and material libraries, as well as machine postprocessor libraries. Postprocessors enable you to convert the toolpath information into the NC code required by a specific machine control.

Surfcam uses a point-and-click Windows environment that most users will find comfortable. It also uses a tree structured menu system similar to earlier versions of the product, as well as CAD products from Autodesk and Cadkey. A customizable toolbar, icons, fonts, and colors enable you to personalize the software.

Display functions, such as panning and rotating, are available at any time by picking dedicated icons located at the top of the display. These two features in particular are among the best we've used, not because of the icons, but because they're so easy to use once they've been selected. You simply move the mouse in the desired direction to perform the operation, and the 3D model follows.

Multiple Axis Machining

We tested the complete Surfcam setup, which includes 2-, 3-, 4-, and 5-axis milling (with simultaneous 4- and 5-axis) and lathe and Nurbs options. "Simultaneous" means the system is capable of simultaneously moving the cutter in the number of axis specified. This feature permits you to machine more complex parts, such as geometries that contain pockets and undercuts, in one setup. Fewer setups save machine and operator time. Also, it's possible to machine normal to the surface, which minimizes scallops and improves surface quality.

Surfcam offers a feature that protects against gouging, which minimizes scrap parts. Gouge protection allows for the maximum amount of material removal without interfering (gouging) with adjacent surfaces. Surfcam also provides clamp avoidance if the clamps and fixtures are included in the design. Surfcam enables you to indicate the direction of cuts, the side of the surface to be cut, and the corner of the surface at which the cut begins. It is possible to make changes to these settings using simple surface editing commands. Surfcam supports cutters of various shapes, such as square end, ball end, bull nose, tear drop, and keycutter. Roughing routines are automatically generated by specifying a few parameters. We found that Surfcam's 2-axis contouring and pocket milling-which may contain islands-works well. Various options are available for roughing and finishing, such as depth per pass and width of cut.

Most milling machines approximate the computer surface using point-to-point linear movements. Widely spaced points produce a less accurate surface. Some CAM packages require that you specify the distance between these points, which requires guess work to get the desired results. Too few of points results in an inaccurate surface, while too many points results in a larger-than-necessary NC program which increases machining time. Surfcam permits you to enter the maximum chordal deviation, giving you an exact understanding of the machined surface and full control over surface accuracy.

Other Features

The lathe features were also easy to use. They provide turning, boring, facing, grooving, drilling, and threading. The wire EDM functions, however, were disappointing. Rather than using an interactive approach, Surfcam creates upper and lower toolpaths using the 2-axis milling features and then postprocesses both into a finished 4-axis NC program. Interactive toolpath editing is another important feature of Surf-cam. It provides a visual method of changing, adding, and deleting tool movements before running the postprocessor. A text editor is provided for making changes to the NC code that has already been postprocessed. Surfcam enables you to view the cutter moving across the material, but it doesn't simulate the removal of material.

Surfcam's postprocessing capabilities are among the best we've encountered. Surfcam provides more than 75 standard posts that can be easily customized for the specific needs of a particular machine tool, even those with strange NC code formats. Poor postprocessors limit the usefulness of many PC-based CAM packages. Time is lost if you must edit the NC code.

Linking to 3D Digitizing

Surfcam enables you to read x, y, z coordinate data produced by 3D digitizing systems, such as those available from Polhemus, Digibotics, and Laser Design. From the point data, Surfcam creates splines, surfaces, and eventually toolpaths. We tested this feature in an earlier version of the software and found it to be exceptional.

A direct interface is available for users of Faro Technologies Metrecom device. Metrecom is a six degrees of freedom articulated measurement device for 3D design, reverse engineering, and interactive toolpath generation. The interface allows you to use Metrecom as a 3D input device with Surfcam, enabling you to copy the precise shape of an existing part. With Surfcam, users can use the program's 3D geometry creation features to produce machinable surfaces.

Getting Started

The installation procedure, which runs within Windows, is clean and straightforward. You are given the option to install it to run either in inch or metric mode. We tried both. Documentation is written clearly and is easy to understand. Absent, however, is a step-by-step tutorial which would be helpful.

Surfcam requires a hardware lock called a Software Interface Module (SIM), also referred to as a dongle, that connects to a parallel port. However, most users prefer not to hassle with SIM devices. While Surfware claims that the SIM does not affect the operation of parallel devices, we found that our Epson Stylus 800 printer does not work properly with it. SIM devices do prevent illegal copying of software, but other less cumbersome methods are effective also.

Future Products

The current DOS offering supports up to 16 megabytes of extended memory, but it is not a 32-bit protected mode application. Surfware personnel explained to us that there are no plans to add it. The company plans to ship a new Windows NT product line in early 1994. It would have been released sooner, but Surfware claims it could not find a SIM device that would work properly with NT. For now, the company is pushing the Windows 3.1 version.

As an interesting side note, Surfcam started developing the Windows product about three years ago to make sure that they would be among the first to market. And as manufacturers make the transition to Windows software, the company plans to support its DOS products as long as there is demand.

Robert Simon is President of Quality Machine, Loveland, CO. Industry consultant Terry Wohlers is President of Wohlers Associates, Fort Collins, CO.

Surfcam 5. A 2- to 5-axis CAM package designed for 3D surface modeling and CNC machining. Close Competition: Gibbs and Associates' Gibbs System ($5,000 to $7,000); CNC Software Inc.'s Mastercam ($495 to $12,000); Point Control Co.'s Smartcam ($4,000 to $10,000). Input/Output: Supports DXF, CADL, CADkey surfaces, MicroStation 5, IGES, CSF, DES, FST, NCAL/NCAD, SPAC, VDA, APTCL, and x, y, z coordinate data. Hardware: Windows requires 386/486 PC, 4 megabytes (mb) RAM, math coprocessor, 10 mb of disk space. DOS requires 286/386/486 PC, 2 mb RAM, math coprocessor, 10 mb of disk space. Installation of both require about 17.6 mb of disk space. Support/Upgrade: 90 days of software maintenance. Dealers provide installation, training, and 90 days of phone and fax support. Price: $2,500 for 2-axis machining to $14,000 for 5-axis machining. Lathe and Nurbs upgrades are $1,500 and $2,500. Surfware Inc., San Fernando, CA 91340; 800/488-3615, 818/361-5605; Fax: 818/361-1919 Circle 159

Surfware Surfcam 5 Scoring

Ease of use llll, Compatibility lll, Support llll, Basic Functions lll, Application Functions llll, Overall Score llll.

l Poor, ll Fair, lll Good, llll Excellent

Pros: Easy to learn software offering impressive 32-bit performance, coupled with advanced surface machining features.

Cons: Wire EDM feature not fully developed; step-by-step tutorial is missing.

Every effort has been made to make this review fair, accurate, and complete. Scores listed are summaries; for a copy of the detailed scores and scoring system, please call Alicia Ellis at 216/696-7000, ext. 2250 or fax 216/696-1309. Ask for a copy of the Surfware Surfcam 5 Detailed Scores.

Copyright 1994 by Robert Simon and Terry T. Wohlers