Published in Galleries on 3/01/2018 by Ballscrew Guys
Ballscrew Guys offers on site field service to fix and restore positioning accuracy to your Accurpress and Accurshear backgauges.
Accurpress Press Brakes
The Accurpress series of Press Brakes are a staple in manufacturing across the US. Seems that almost every shop has one. Ballscrew Guys does not often offer flat rate pricing for Back Gauge repairs and refurbishment. Often because correction of the conditions which caused the CNC Motion System failure and its subsequent repair time is difficult to forecast. Typically, we can complete an Accurpress back gauge refurbishment in (2) 8 hour production shifts. But there are often many other constraints, such as safety and controller side issues, which may require the repair to take longer.
Accurpress Back Gauge
One of the more common back gauge styles and designs we have found on the lighter and medium Pres Brakes. On this style the ball screws and motion system components are surrounded inside specialty extruded tubing. On these model types, access to the ball screw ball is exceptionally limited. So the entire back gauge assembly has to be disconnected from the machine.
Back Gauge Removal
A safety plan needs to be formed prior to back gauge removal. Before service, the rear of the machine needs to be cleaned out. The floor kept free of debris and trip hazards. In this photo we are using a mobile hydraulic table cart to carry the load of the back gauge. We have used overhead crane systems in the past, but prefer some type of ground based support for refurbishing your back gauge.
Accurpress Back Gauge Ball Screw Drive Belt
Here we have a disconnected Accurpress Back Gauge tipped up on it's end. This is required on this type to refurbish or replace the ball screws. Notice the toothed serpentine belt in the image. One this model, one drive motor moves both back gauge screw. So it is critical to note and confirm position and alignment of ALL components during the refurbishment process. Ballscrew Guys strongly recommends the installation of a new belt and ball screw end bearings whenever this service is performed.
Accurpress OEM Ball Screws
Here are shown two New ballscrews purchased from Accurpress. Upon initial inspection, we were somewhat puzzled by these ball screws. The rotational resistance (drag torque) of these screws were different. In simple terms, one ball nut spinned way easier than the other. We called Accurpress to verify if the reason for this was because one screw was position on a Master/Drive side, the other left passive. A typical combination found in some dual screw same-axis CNC motion systems. The Vendor's response was "They Are Identical", which they were not. At least in the Ballscrew Guys universe. So, Before installation, we rebuilt both with Grade 10 machine tool bearings, making both spin and rotate with identical force and energy.
Dirt and Grit
The main culprit in wearing out Accurpress Back Gauges is usually not the years of production. It is the grit and contamination which fills the motion system of the Back Gauge assembly. This particular back gauge was located next to a CNC Plasma burn table. Over the years, the dust and debris from the cutting station ended up getting blown onto the back gauge. The lubrication of which was tacky, making all of this material coat the motion systems components. All of this is cleaned off when we service equipment. We make it a point to work with your facility maintenance staff and show them how to avoid CNC motion system contamination in the future.