Recently, I was introduced to Amann Girrbach’s (AG) newly released Mikro, 4-axis mill. This mill stands alone in its class of low cost, small, heavy-duty 4-axis mills. During this introduction, I toured the AG manufacturing facility and was very impressed with the manufacturing process for this mill.
First, the Mikro has a unibody construction. The mill design includes a one piece casting that is about 1-1.5 inches thick. This casting is the entire mill chamber and the framework for nearly all the additional parts such as rails, controls spindle and more. After casting, the chamber is placed in a large frame CNC mill, where the raw cast chamber is milled to exacting tolerances for placement of many essential additional mill parts. Holes are drilled and tapped and additional areas are milled precisely and accurately. The first time I watched the manufacturing process of this mill, the engineering of how this mill was designed and constructed blew me away. Next, the price point (about $25k including CAM) most labs can afford. Here is how I see it fitting into almost any dental lab worldwide.
At $25K, the cost of ownership is only about $500 a month with a five year lease. Add a quality sintering furnace (*DO NOT buy into an inexpensive furnace), $10k and the monthly cost is about $700. If your outsource bill for dry-milled products is in the $1200+ a month range, the ROI likely works to make you more profitable. If you are hand waxing anything, I would add $5 per framework unit and about $10 a unit for full contour, including diagnostic wax ups as the savings when covering to milling wax. This is not exact as all labs spend different amounts of time on procedures. You can figure out your direct cost in your unique workflow. To do so, include cost of labor for die spacer and to fabricate the waxed units. I would then subtract about 5-8 minutes labor for scan, design and CAM. In addition, mills don’t have as many bad days as technicians. If you have one of these analog techs, by adding a mill your quality will immediately become more consistent.
Next topic, Return on investment (ROI): If economics of an ROI suggests you need a low cost mill, you may need to send out a small percentage of the cases that require a 5-axis mill. On another note, if you already have a 5-axis mill, the Mikro is a great economical way to add a second mill to production in your facility. You already have 5-axis capability and 98% of the cases can be milled in 4-axis, why not save the money and add a 4-axis rather than a 5? I like to use the rule of 80% full as a point in which it’s time to add another mill. It’s pretty involved for me to explain how much more efficient a lab’s workflow will become with an additional spindle. I’ll save it for another blog.
For more on selecting a sintering furnace go here: http://cap-us.com/2014/04/10/a-look-at-sintering/
For more information on the Mikro, check out:
http://cap-us.com/products/amann-girrbach-milling-machines/?postTabs=1 Thanks for reading,
Bob Cohen, CDT