Automated Die Lubrication in Forging Applications
May 2023 | Troy Turnbull from FIA Magazine May 2023
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The industrial world is facing many technological changes which increases the urgent demand for premium quality products and services that can only be supplied by a high level of productivity. These expectations show that global industrial companies are preferring automation to reduce operational costs, increase productivity, and enhance the consistency of processes for overall improvement in quality.
These improvements can easily be achieved by implementing automated lubrication systems that perform consistently and help control operational processes. These solutions are widely available for greater efficiency and productivity of facilities for many industries, including forging, for automation applications.
There are a variety of automated solutions for improved lubrication management from simple die mounted spray nozzles, reciprocating applicators, to full 6-axis robots or cobots. All can be completed unattended with consistency and speed but are built on a foundation of correct lubricant choice including dilution ratio if applicable.
Lubricants
The very nature of using lubricants is the reduction of friction that can cause unnecessary force or delays in your process with parts sticking to dies. The proper lubricant and application enhance both issues and can help lower your power use.
If you can’t remember the last time you changed lubricants, consider meeting with your lubricant supplier to help determine the best choice for each part you manufacture as one size does not fit all. If using a graphite mixture or oil-based product, maybe look into a ‘soak based’ synthetic. This search may include establishing a dilution ratio for the lubricant.
When mixing is necessary, many companies continue to use the ‘bucket brigade’ by hand measuring and manually stirring their ratios. This not only has a built-in error factor, but is yet another use of valuable labor that could be better spent elsewhere.
Proportional mixing machines are a productive and constant means of creating a uniform formula (within 1%), and properly stir the mix as too much agitation can degrade the lube. These systems are part of your automation structure as they mix lubricants unattended and deliver it to your application devices.
Application
Application automation is another excellent choice for improvement so that die lubrication is very consistent. Many facilities choose to have operators hand spray their dies using a long wand. Although the person does their best to coat the surfaces the same every time, spending long hours press side only equates to over or under coverage and a very tired arm.
Where and how much of the correct lubricant being applied is imperative in an automated setting. Spray nozzles are a key component as they can help regulate the amount of lubricant along with the shape of the spray. Pin-pointing the location of spray is essential to prevent overuse and proper functionality. However, having a proper delivery system to the nozzle will manage timing and volume automatically and even store the entire recipe per part. The recipe can then be ‘locked’ so that manipulation cannot take place. Up to 24 nozzles can be independently programmed on these delivery systems to shoot lube, air, or skip cycles.
Many times, manual changes occur in the plant due to what seems to be lubrication failure. Parts are not forming correctly or releasing so operators adjust as necessary to keep production moving. However, after close examination of the process will indicate many times that an overcompensation or under-utilization of lube is being applied. This is due to either an improper dilution ratio, or a bad nozzle that is not spraying correctly. Nozzles typically get obstructed from the absence of maintenance. Again, having a comprehensive delivery system will notice dormancy and will indicate that a purge of the lines and nozzles is required. If using a water-based lubricant, have your water tested for hardness to prevent a buildup of calcium which will restrict a line.
Flow meters also aid to indicate under or over-utilization of lube signaling a problem or an override. This data can be electronically sent to remote devices for analysis and comparison to production records.
Spray Automation
The simplest of such an automated system is a pedestal style controller with injectors to die-mounted nozzles that are held in place with a heavy-duty magnetic base. The nozzles can be easily manipulated to spray lubricants where required, then relocated on the next die change. Again, the recipe is stored in the HMI control center, so reprogramming is not required but instead just relocation of the nozzles. The spray can be actuated by the press control for a fully automated operation, or for manual activation, a foot pedal or hand button can be used. Although the latter method is not full automation, it does eliminate the need for an operator to hand spray the dies.
A reciprocating spray machine is ideal for many forging applications as it automatically extends the lubricating nozzles into the die area and accurately layers the target zone with lube and can even blow air separately to remove debris. The lubricant is sprayed onto the dies using spray heads mounted on a manifold. Typically, these manifolds are custom designed to cover your unique die space yet can be adjusted for precise spray location.
Reciprocators traverse the manifold quickly into the die area at speeds up to 50 inches per second. Lube and/or air can be fired from the nozzles in a cone shape when stopped, or in a fan shape when swept (spray during motion). The extent of the traverse, spray location and time all are stored as a recipe in the electronic controls package.
Horizontal reciprocators work well in typical style presses or hammers with extension of the spray manifold into the die area from 24” to 48” or more. However, vertical reciprocators are ideal when dies move laterally, such as an upsetter. These spray systems are mounted on the press platens above the die area and vertically traverse down to spray the die area. Automated lubricant reciprocating systems are regulated by a PLC-driven, HMIcontrolled command center that can store part recipes for fast retrieval and complete process management.
The most comprehensive automated solutions are the use of robots or cobots. These machines can extract parts, air-blast debris, and spray the die area with lubricants. The robot can manipulate the nozzles or manifolds like a human, mimicking the same application process consistently.
Robots can be rigged with a single nozzle and programmed to isolate the spray to the exact location with the specified lube volume and then progress to the next cavity. Or outfit the robot with a manifold loaded with spray heads that precisely lubricate a host of cavities simultaneously.
Getting Started
The best place to start is at the end! Where do you want the automation process to be in several years? Establishing a 3- to 5-year strategy can help stakeholders prioritize how to replace and update critical systems and subsystems and set up a game plan for efficient execution. Having a blueprint for a plant’s long-term automation strategy provides sufficient training and ramp-up time while still delivering ROI. These solutions require capital investment upfront, but the long-term return is hard to ignore.
Considerations such as part volume, die changeovers, required maintenance, implementation personnel, and budgets must all be part of the calculation. An authorized system integrator (ASI) can help companies achieve their goals with comprehensive solutions. An ASI partner can offer tried-and-true ideas to mitigate risk and build efficiencies into new and existing processes.
