Magento 2:: Join Collection

$recycleCollection = $this->_postFactory->create()->getCollection()
                                ->addFieldToFilter('main_table.customer_id', array('eq' => $customer_id))
                                ->addFieldToFilter('main_table.website_id', array('eq' => $websiteId))
                                ->addFieldToFilter('main_table.is_bulk', array('eq' => $isbulk));
        $recycleCollection->getSelect()->joinLeft(
            ['fedexrecycle' => $this->_tableName4],
            "main_table.recycle_order_id = fedexrecycle.recycle_order_id",
            ['shipping_label_path']
        );
        $recycleCollection->setOrder('main_table.recycle_order_id','desc');
        $recycleCollection->setPageSize($limit)->setCurPage($start_from)->load();
        
        return $recycleCollection;