CUSTOM WORKHOLDING, COMPOSITE PRINTING
At Lean Machine we have recently added a Markforged Composite 3D printer, which has rapidly become a great new tool in our capabilities. Besides the ability to print strong mechanical composite parts for Jigs, Fixtures, Workholding, Tooling, R&D, and other applications, we have been able to make rapid progress in DFAM (Design For Additive Manufacture). We're discovering new opportunities and intricacies in this design process on a daily basis!
One of the greatest abilities of DFAM and Additive Manufacturing is to quickly solve emerging technical challenges around the shop, in an Agile fashion with minimal labour, at the very least without demanding the time of already busy machining centers and conventional production processes. When a new challenge developed on Extrusion processing on our new 5-Axis Gantry CNC, we had just the ticket to solve it...
Our initial configuration for workholding on this machine was based off a previously successful design on another machine, and further improved, consisting of quickly-moveable machine vises down the length of the table. This had proven very effective on the prior generation extrusion workcenter, and we took it a step further with higher quality, more rigid components to maximize the capabilities.
The challenge arose when we realized that to avoid machine collisions, the stickout of many workpieces was such that lighter cutting was required to achieve our standards of cut quality, so our Engineering team got to work on improvements to deliver greater performance. A new "Secondary" vise design was quickly developed in a matter of days, in fact designed entirely around the machine model, to bring the work holding as close to the end cut zones as possible.
This new vise design incorporates Agile and DFAM design theories, and practical expertise from decades of Machining mastery. The choice to build many parts from purpose-engineered reinforced composites is no coincidence: These materials provide excellent dampening to vibrations from high RPM cutting, thereby delivering not only improved cut quality and speeds, but increased tool life as well.
The hard-working mechanical parts that give a vise its clamping capability are of course made from metal alloys, using almost entirely off-the-shelf components (McMaster-Carr in this case, ever-popular among Mech/Mfg Engineers thanks to one-day delivery). Roller thrust bearings, Steel and brass trapezoidal leadscrew components, and special hand-brakes for guideway mounting the vises bring the inner workings together. The vise bases are 5-axis machined in one operation on the same machine they are built for.
Over two dozen 3D printed composite parts are used in each vise, but most of these are small pressed in parts to reinforce fastening areas. The larger parts are reinforced as necessary with either high strength fiberglass, or continuous carbon fiber, in areas that require greater mechanical strength, undergo heavier compressive forces and other stress. Metal components and fasteners can be printed into the parts, or pressed in afterwards. Unlike machined metal parts, the printed parts take substantially less time to program than to design. Printing them can take a days for larger parts, but the process is unmanned and scrapped prints are extremely rare.
Assembly is a breeze, and the vises are ready for service! Thanks to the modular construction, any part that needs to be changed can be swapped on the fly, for example if a particular job requires a different jaw style.
Time to make some chips!